---
_id: '64877'
author:
- first_name: Behnood
full_name: Taheri, Behnood
last_name: Taheri
- first_name: Denis
full_name: Kopylov, Denis
id: '98502'
last_name: Kopylov
- first_name: Manfred
full_name: Hammer, Manfred
id: '48077'
last_name: Hammer
orcid: 0000-0002-6331-9348
- first_name: Torsten
full_name: Meier, Torsten
id: '344'
last_name: Meier
orcid: 0000-0001-8864-2072
- first_name: Jens
full_name: Förstner, Jens
id: '158'
last_name: Förstner
orcid: 0000-0001-7059-9862
- first_name: Polina R.
full_name: Sharapova, Polina R.
id: '60286'
last_name: Sharapova
citation:
ama: Taheri B, Kopylov D, Hammer M, Meier T, Förstner J, Sharapova PR. Gain-induced
spectral non-degeneracy in type-II parametric down-conversion. arXiv. Published
online 2026. doi:10.48550/ARXIV.2603.01656
apa: Taheri, B., Kopylov, D., Hammer, M., Meier, T., Förstner, J., & Sharapova,
P. R. (2026). Gain-induced spectral non-degeneracy in type-II parametric down-conversion.
ArXiv. https://doi.org/10.48550/ARXIV.2603.01656
bibtex: '@article{Taheri_Kopylov_Hammer_Meier_Förstner_Sharapova_2026, title={Gain-induced
spectral non-degeneracy in type-II parametric down-conversion}, DOI={10.48550/ARXIV.2603.01656},
journal={arXiv}, author={Taheri, Behnood and Kopylov, Denis and Hammer, Manfred
and Meier, Torsten and Förstner, Jens and Sharapova, Polina R.}, year={2026} }'
chicago: Taheri, Behnood, Denis Kopylov, Manfred Hammer, Torsten Meier, Jens Förstner,
and Polina R. Sharapova. “Gain-Induced Spectral Non-Degeneracy in Type-II Parametric
down-Conversion.” ArXiv, 2026. https://doi.org/10.48550/ARXIV.2603.01656.
ieee: 'B. Taheri, D. Kopylov, M. Hammer, T. Meier, J. Förstner, and P. R. Sharapova,
“Gain-induced spectral non-degeneracy in type-II parametric down-conversion,”
arXiv, 2026, doi: 10.48550/ARXIV.2603.01656.'
mla: Taheri, Behnood, et al. “Gain-Induced Spectral Non-Degeneracy in Type-II Parametric
down-Conversion.” ArXiv, 2026, doi:10.48550/ARXIV.2603.01656.
short: B. Taheri, D. Kopylov, M. Hammer, T. Meier, J. Förstner, P.R. Sharapova,
ArXiv (2026).
date_created: 2026-03-10T15:37:22Z
date_updated: 2026-03-10T15:41:18Z
department:
- _id: '15'
- _id: '569'
- _id: '170'
- _id: '293'
- _id: '35'
- _id: '34'
- _id: '61'
- _id: '230'
- _id: '623'
- _id: '429'
doi: 10.48550/ARXIV.2603.01656
language:
- iso: eng
project:
- _id: '168'
name: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat
(B07*)
- _id: '56'
name: TRR 142 - Project Area C
- _id: '174'
name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen
Systemen: Eine theoretische Analyse'
publication: arXiv
status: public
title: Gain-induced spectral non-degeneracy in type-II parametric down-conversion
type: journal_article
user_id: '16199'
year: '2026'
...
---
_id: '65575'
abstract:
- lang: eng
text: For the ever-growing field of quantum information processing, large-scale,
efficient multiport interferometers serving as photonic processors are required.
In this context, the suitability of quantum walks as the interferometric base
for universal computation has been theoretically proven. In this work, we bridge
the gap between theoretical proposals and state-of-the-art experimental capabilities
by providing the recipe for the implementation of a universal photonic processor
in discrete-time quantum walks. Specifically, we present the protocol for translating
arbitrary linear transformations into the coin and step operator of a quantum
walk and map these to the experimental parameters of the established time-multiplexed
platform [A. Schreiber , Phys. Rev. Lett. , 050502 (2010)]. We show that our interface
is highly scalable and resource efficient due to the hybrid encoding consisting
of multiple degrees of freedom. Finally, we prove that our system is highly resilient
against experimental imperfections and show that it compares favorably against
existing architectures.
article_number: '054011'
author:
- first_name: Jonas
full_name: Lammers, Jonas
last_name: Lammers
- first_name: Laura
full_name: Ares, Laura
last_name: Ares
- first_name: Federico
full_name: Pegoraro, Federico
id: '88928'
last_name: Pegoraro
- first_name: Philip
full_name: Held, Philip
id: '68236'
last_name: Held
- first_name: Benjamin
full_name: Brecht, Benjamin
id: '27150'
last_name: Brecht
orcid: '0000-0003-4140-0556 '
- first_name: Jan
full_name: Sperling, Jan
id: '75127'
last_name: Sperling
orcid: 0000-0002-5844-3205
- first_name: Christine
full_name: Silberhorn, Christine
id: '26263'
last_name: Silberhorn
citation:
ama: Lammers J, Ares L, Pegoraro F, et al. Resource-efficient universal photonic
processors based on time-multiplexed hybrid architectures. Physical Review
Applied. 2026;25(5). doi:10.1103/x99y-2sms
apa: Lammers, J., Ares, L., Pegoraro, F., Held, P., Brecht, B., Sperling, J., &
Silberhorn, C. (2026). Resource-efficient universal photonic processors based
on time-multiplexed hybrid architectures. Physical Review Applied, 25(5),
Article 054011. https://doi.org/10.1103/x99y-2sms
bibtex: '@article{Lammers_Ares_Pegoraro_Held_Brecht_Sperling_Silberhorn_2026, title={Resource-efficient
universal photonic processors based on time-multiplexed hybrid architectures},
volume={25}, DOI={10.1103/x99y-2sms},
number={5054011}, journal={Physical Review Applied}, publisher={American Physical
Society (APS)}, author={Lammers, Jonas and Ares, Laura and Pegoraro, Federico
and Held, Philip and Brecht, Benjamin and Sperling, Jan and Silberhorn, Christine},
year={2026} }'
chicago: Lammers, Jonas, Laura Ares, Federico Pegoraro, Philip Held, Benjamin Brecht,
Jan Sperling, and Christine Silberhorn. “Resource-Efficient Universal Photonic
Processors Based on Time-Multiplexed Hybrid Architectures.” Physical Review
Applied 25, no. 5 (2026). https://doi.org/10.1103/x99y-2sms.
ieee: 'J. Lammers et al., “Resource-efficient universal photonic processors
based on time-multiplexed hybrid architectures,” Physical Review Applied,
vol. 25, no. 5, Art. no. 054011, 2026, doi: 10.1103/x99y-2sms.'
mla: Lammers, Jonas, et al. “Resource-Efficient Universal Photonic Processors Based
on Time-Multiplexed Hybrid Architectures.” Physical Review Applied, vol.
25, no. 5, 054011, American Physical Society (APS), 2026, doi:10.1103/x99y-2sms.
short: J. Lammers, L. Ares, F. Pegoraro, P. Held, B. Brecht, J. Sperling, C. Silberhorn,
Physical Review Applied 25 (2026).
date_created: 2026-05-07T07:00:08Z
date_updated: 2026-05-07T07:01:09Z
department:
- _id: '623'
- _id: '15'
- _id: '170'
- _id: '706'
- _id: '429'
doi: 10.1103/x99y-2sms
intvolume: ' 25'
issue: '5'
language:
- iso: eng
publication: Physical Review Applied
publication_identifier:
issn:
- 2331-7019
publication_status: published
publisher: American Physical Society (APS)
status: public
title: Resource-efficient universal photonic processors based on time-multiplexed
hybrid architectures
type: journal_article
user_id: '75127'
volume: 25
year: '2026'
...
---
_id: '65574'
article_number: '052413'
author:
- first_name: Julien
full_name: Pinske, Julien
last_name: Pinske
- first_name: Jan
full_name: Sperling, Jan
id: '75127'
last_name: Sperling
orcid: 0000-0002-5844-3205
- first_name: Klaus
full_name: Mølmer, Klaus
last_name: Mølmer
citation:
ama: Pinske J, Sperling J, Mølmer K. Entangling power of nonentangling channels.
Physical Review A. 2026;113(5). doi:10.1103/vy93-dnc8
apa: Pinske, J., Sperling, J., & Mølmer, K. (2026). Entangling power of nonentangling
channels. Physical Review A, 113(5), Article 052413. https://doi.org/10.1103/vy93-dnc8
bibtex: '@article{Pinske_Sperling_Mølmer_2026, title={Entangling power of nonentangling
channels}, volume={113}, DOI={10.1103/vy93-dnc8},
number={5052413}, journal={Physical Review A}, publisher={American Physical Society
(APS)}, author={Pinske, Julien and Sperling, Jan and Mølmer, Klaus}, year={2026}
}'
chicago: Pinske, Julien, Jan Sperling, and Klaus Mølmer. “Entangling Power of Nonentangling
Channels.” Physical Review A 113, no. 5 (2026). https://doi.org/10.1103/vy93-dnc8.
ieee: 'J. Pinske, J. Sperling, and K. Mølmer, “Entangling power of nonentangling
channels,” Physical Review A, vol. 113, no. 5, Art. no. 052413, 2026, doi:
10.1103/vy93-dnc8.'
mla: Pinske, Julien, et al. “Entangling Power of Nonentangling Channels.” Physical
Review A, vol. 113, no. 5, 052413, American Physical Society (APS), 2026,
doi:10.1103/vy93-dnc8.
short: J. Pinske, J. Sperling, K. Mølmer, Physical Review A 113 (2026).
date_created: 2026-05-07T06:57:10Z
date_updated: 2026-05-07T06:58:39Z
department:
- _id: '623'
- _id: '15'
- _id: '170'
- _id: '706'
- _id: '429'
doi: 10.1103/vy93-dnc8
intvolume: ' 113'
issue: '5'
language:
- iso: eng
publication: Physical Review A
publication_identifier:
issn:
- 2469-9926
- 2469-9934
publication_status: published
publisher: American Physical Society (APS)
status: public
title: Entangling power of nonentangling channels
type: journal_article
user_id: '75127'
volume: 113
year: '2026'
...
---
_id: '65777'
abstract:
- lang: eng
text: "Abstract\r\n In this work,
we address the numerical identification of entanglement in dynamical scenarios.
To this end, we consider different programs based on the restriction of the evolution
to the set of separable (i.e., non-entangled) states, together with the discretization
of the space of variables for numerical computations. As a first approach, we
apply linear splitting methods to the restricted, continuous equations of motion
derived from variational principles. We utilize an exchange interaction Hamiltonian
to confirm that the numerical and analytical solutions coincide in the limit of
small time steps. The application to different Hamiltonians shows the wide applicability
of the method to detect dynamical entanglement. To avoid the derivation of analytical
solutions for complex dynamics, we consider variational, numerical integration
schemes, introducing a variational discretization for Lagrangians linear in velocities.
Here, we examine and compare two approaches: one in which the system is discretized
before the restriction is applied, and another in which the restriction precedes
the discretization. We find that the ‘first-discretize-then-restrict’ method becomes
numerically unstable, already for the example of an exchange-interaction Hamiltonian,
which can be an important consideration for the numerical analysis of constrained
quantum dynamics. Thereby, broadly applicable numerical tools, including their
limitations, for studying entanglement over time are established for assessing
the entangling power of processes that are used in quantum information theory."
article_number: '225303'
author:
- first_name: Christian
full_name: Offen, Christian
last_name: Offen
- first_name: Boris Edgar
full_name: Wembe Moafo, Boris Edgar
id: '95394'
last_name: Wembe Moafo
orcid: 0000-0002-6085-8071
- first_name: Laura
full_name: Ares, Laura
last_name: Ares
- first_name: Jan
full_name: Sperling, Jan
id: '75127'
last_name: Sperling
orcid: 0000-0002-5844-3205
- first_name: Sina
full_name: Ober-Blöbaum, Sina
id: '16494'
last_name: Ober-Blöbaum
citation:
ama: 'Offen C, Wembe Moafo BE, Ares L, Sperling J, Ober-Blöbaum S. Numerical approaches
to entangling dynamics from variational principles. Journal of Physics A: Mathematical
and Theoretical. 2026;59(22). doi:10.1088/1751-8121/ae6d51'
apa: 'Offen, C., Wembe Moafo, B. E., Ares, L., Sperling, J., & Ober-Blöbaum,
S. (2026). Numerical approaches to entangling dynamics from variational principles.
Journal of Physics A: Mathematical and Theoretical, 59(22), Article
225303. https://doi.org/10.1088/1751-8121/ae6d51'
bibtex: '@article{Offen_Wembe Moafo_Ares_Sperling_Ober-Blöbaum_2026, title={Numerical
approaches to entangling dynamics from variational principles}, volume={59}, DOI={10.1088/1751-8121/ae6d51},
number={22225303}, journal={Journal of Physics A: Mathematical and Theoretical},
publisher={IOP Publishing}, author={Offen, Christian and Wembe Moafo, Boris Edgar
and Ares, Laura and Sperling, Jan and Ober-Blöbaum, Sina}, year={2026} }'
chicago: 'Offen, Christian, Boris Edgar Wembe Moafo, Laura Ares, Jan Sperling, and
Sina Ober-Blöbaum. “Numerical Approaches to Entangling Dynamics from Variational
Principles.” Journal of Physics A: Mathematical and Theoretical 59, no.
22 (2026). https://doi.org/10.1088/1751-8121/ae6d51.'
ieee: 'C. Offen, B. E. Wembe Moafo, L. Ares, J. Sperling, and S. Ober-Blöbaum, “Numerical
approaches to entangling dynamics from variational principles,” Journal of
Physics A: Mathematical and Theoretical, vol. 59, no. 22, Art. no. 225303,
2026, doi: 10.1088/1751-8121/ae6d51.'
mla: 'Offen, Christian, et al. “Numerical Approaches to Entangling Dynamics from
Variational Principles.” Journal of Physics A: Mathematical and Theoretical,
vol. 59, no. 22, 225303, IOP Publishing, 2026, doi:10.1088/1751-8121/ae6d51.'
short: 'C. Offen, B.E. Wembe Moafo, L. Ares, J. Sperling, S. Ober-Blöbaum, Journal
of Physics A: Mathematical and Theoretical 59 (2026).'
date_created: 2026-06-05T07:37:43Z
date_updated: 2026-06-05T07:38:44Z
department:
- _id: '623'
- _id: '15'
- _id: '170'
- _id: '706'
- _id: '429'
doi: 10.1088/1751-8121/ae6d51
intvolume: ' 59'
issue: '22'
language:
- iso: eng
publication: 'Journal of Physics A: Mathematical and Theoretical'
publication_identifier:
issn:
- 1751-8113
- 1751-8121
publication_status: published
publisher: IOP Publishing
status: public
title: Numerical approaches to entangling dynamics from variational principles
type: journal_article
user_id: '75127'
volume: 59
year: '2026'
...
---
_id: '66665'
abstract:
- lang: eng
text: Multimode quantum light has promising applications in many areas of physics,
such as quantum communications and quantum computing. However, its multimode nature
also makes it challenging to measure its properties. Recently [I. Barakat et al.,
Optica Quantum 3, 36 (2025)], a technique for the simultaneous measurement of
squeezing of multiple broadband modes based on a phase-sensitive amplification
approach was experimentally implemented using a setup that effectively corresponds
to an SU(1,1) interferometer. Here, we aim to provide a complete theoretical analysis
of the modal structure of (generally unbalanced) SU(1,1) interferometers and a
detailed theoretical formal derivation of the framework for this technique. Utilizing
the joint Schmidt decomposition of the transfer functions, we investigate the
shape and phase profiles of the modes of the SU(1,1) interferometer and its components
[parametric down-conversion (PDC) sections] for different parametric gain regimes.
We discover a complicated interplay between the PDC modes and the modes of the
entire interferometer, and analyze it by using their overlap coefficients as a
similarity measure. Finally, we develop a rigorous processing method for the aforementioned
multimode squeezing measurement technique and discuss necessary approximations
to make this method experimentally feasible.
article_number: '033139'
article_type: original
author:
- first_name: Dennis
full_name: Scharwald, Dennis
id: '55907'
last_name: Scharwald
orcid: 0009-0007-5654-5412
- first_name: Polina
full_name: Sharapova, Polina
id: '60286'
last_name: Sharapova
citation:
ama: Scharwald D, Sharapova P. Characterization of spatial Schmidt modes in high-gain
SU(1,1) interferometers. Physical Review Research. 2026;8(3). doi:10.1103/ph64-ts39
apa: Scharwald, D., & Sharapova, P. (2026). Characterization of spatial Schmidt
modes in high-gain SU(1,1) interferometers. Physical Review Research, 8(3),
Article 033139. https://doi.org/10.1103/ph64-ts39
bibtex: '@article{Scharwald_Sharapova_2026, title={Characterization of spatial Schmidt
modes in high-gain SU(1,1) interferometers}, volume={8}, DOI={10.1103/ph64-ts39},
number={3033139}, journal={Physical Review Research}, publisher={American Physical
Society (APS)}, author={Scharwald, Dennis and Sharapova, Polina}, year={2026}
}'
chicago: Scharwald, Dennis, and Polina Sharapova. “Characterization of Spatial Schmidt
Modes in High-Gain SU(1,1) Interferometers.” Physical Review Research 8,
no. 3 (2026). https://doi.org/10.1103/ph64-ts39.
ieee: 'D. Scharwald and P. Sharapova, “Characterization of spatial Schmidt modes
in high-gain SU(1,1) interferometers,” Physical Review Research, vol. 8,
no. 3, Art. no. 033139, 2026, doi: 10.1103/ph64-ts39.'
mla: Scharwald, Dennis, and Polina Sharapova. “Characterization of Spatial Schmidt
Modes in High-Gain SU(1,1) Interferometers.” Physical Review Research,
vol. 8, no. 3, 033139, American Physical Society (APS), 2026, doi:10.1103/ph64-ts39.
short: D. Scharwald, P. Sharapova, Physical Review Research 8 (2026).
date_created: 2026-08-05T11:51:21Z
date_updated: 2026-08-12T14:29:44Z
department:
- _id: '975'
- _id: '15'
- _id: '623'
- _id: '569'
- _id: '170'
- _id: '35'
- _id: '429'
- _id: '34'
- _id: '502'
doi: 10.1103/ph64-ts39
intvolume: ' 8'
issue: '3'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://journals.aps.org/prresearch/pdf/10.1103/ph64-ts39
oa: '1'
project:
- _id: '56'
name: TRR 142 - Project Area C
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '174'
name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen
Systemen: Eine theoretische Analyse'
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
publication: Physical Review Research
publication_identifier:
issn:
- 2643-1564
publication_status: published
publisher: American Physical Society (APS)
status: public
title: Characterization of spatial Schmidt modes in high-gain SU(1,1) interferometers
type: journal_article
user_id: '55907'
volume: 8
year: '2026'
...
---
_id: '63744'
abstract:
- lang: eng
text: Orbital angular momentum (OAM) modes are an important resource used in various
branches of quantum science and technology due to their unique helical structure
and countably infinite basis. Generating light that simultaneously carries high-order
orbital angular momenta and exhibits quantum correlations is a challenging task.
In this work, we present a theoretical approach to the generation of correlated
Schmidt modes carrying OAM via parametric down-conversion (PDC) in cascaded nonlinear
systems (nonlinear interferometers) pumped by Laguerre–Gaussian beams. We demonstrate
how the number of generated modes and their population can be controlled by varying
the pump parameters, the gain of the PDC process, and the distance between the
crystals. We investigate the angular displacement measurement uncertainty of these
interferometers and demonstrate that it can overcome the classical shot noise
limit.
article_number: '016112'
article_type: original
author:
- first_name: Dennis
full_name: Scharwald, Dennis
id: '55907'
last_name: Scharwald
orcid: 0009-0007-5654-5412
- first_name: Lucas
full_name: Gehse, Lucas
last_name: Gehse
- first_name: Polina
full_name: Sharapova, Polina
id: '60286'
last_name: Sharapova
citation:
ama: Scharwald D, Gehse L, Sharapova P. Schmidt modes carrying orbital angular momentum
generated by cascaded systems pumped with Laguerre–Gaussian beams. APL Photonics.
2025;10(1). doi:10.1063/5.0229802
apa: Scharwald, D., Gehse, L., & Sharapova, P. (2025). Schmidt modes carrying
orbital angular momentum generated by cascaded systems pumped with Laguerre–Gaussian
beams. APL Photonics, 10(1), Article 016112. https://doi.org/10.1063/5.0229802
bibtex: '@article{Scharwald_Gehse_Sharapova_2025, title={Schmidt modes carrying
orbital angular momentum generated by cascaded systems pumped with Laguerre–Gaussian
beams}, volume={10}, DOI={10.1063/5.0229802},
number={1016112}, journal={APL Photonics}, publisher={AIP Publishing}, author={Scharwald,
Dennis and Gehse, Lucas and Sharapova, Polina}, year={2025} }'
chicago: Scharwald, Dennis, Lucas Gehse, and Polina Sharapova. “Schmidt Modes Carrying
Orbital Angular Momentum Generated by Cascaded Systems Pumped with Laguerre–Gaussian
Beams.” APL Photonics 10, no. 1 (2025). https://doi.org/10.1063/5.0229802.
ieee: 'D. Scharwald, L. Gehse, and P. Sharapova, “Schmidt modes carrying orbital
angular momentum generated by cascaded systems pumped with Laguerre–Gaussian beams,”
APL Photonics, vol. 10, no. 1, Art. no. 016112, 2025, doi: 10.1063/5.0229802.'
mla: Scharwald, Dennis, et al. “Schmidt Modes Carrying Orbital Angular Momentum
Generated by Cascaded Systems Pumped with Laguerre–Gaussian Beams.” APL Photonics,
vol. 10, no. 1, 016112, AIP Publishing, 2025, doi:10.1063/5.0229802.
short: D. Scharwald, L. Gehse, P. Sharapova, APL Photonics 10 (2025).
date_created: 2026-01-26T15:48:54Z
date_updated: 2026-02-01T13:19:20Z
department:
- _id: '15'
- _id: '569'
- _id: '170'
- _id: '35'
- _id: '429'
doi: 10.1063/5.0229802
intvolume: ' 10'
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://pubs.aip.org/aip/app/article-pdf/doi/10.1063/5.0229802/20352749/016112_1_5.0229802.pdf
oa: '1'
project:
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '56'
name: TRR 142 - Project Area C
- _id: '174'
name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen
Systemen: Eine theoretische Analyse'
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
publication: APL Photonics
publication_identifier:
issn:
- 2378-0967
publication_status: published
publisher: AIP Publishing
status: public
title: Schmidt modes carrying orbital angular momentum generated by cascaded systems
pumped with Laguerre–Gaussian beams
type: journal_article
user_id: '55907'
volume: 10
year: '2025'
...
---
_id: '63745'
abstract:
- lang: eng
text: Multimode squeezed light is an increasingly popular tool in photonic quantum
technologies, including sensing, imaging, and computation. Meanwhile, the existing
methods of its characterization are technically complicated, which reduces the
level of squeezing, and mostly deal with a single mode at a time. Here, for the
first time, to the best of our knowledge, we employ optical parametric amplification
to characterize multiple squeezing eigenmodes simultaneously. We retrieve the
shapes and squeezing degrees of all modes at once through direct detection followed
by modal decomposition. This method is tolerant to inefficient detection and does
not require a local oscillator. For a spectrally and spatially multimode squeezed
vacuum, we characterize eight strongest spatial modes, obtaining squeezing and
anti-squeezing values of up to −5.2 ± 0.2 dB and 8.6 ± 0.3 dB, respectively, despite
the 50% detection loss. This work, being the first exploration of an optical parametric
amplifier’s multimode capability for squeezing detection, paves the way for the
real-time detection of multimode squeezing.
article_number: '36'
article_type: original
author:
- first_name: Ismail
full_name: Barakat, Ismail
last_name: Barakat
- first_name: Mahmoud
full_name: Kalash, Mahmoud
last_name: Kalash
- first_name: Dennis
full_name: Scharwald, Dennis
id: '55907'
last_name: Scharwald
orcid: 0009-0007-5654-5412
- first_name: Polina
full_name: Sharapova, Polina
id: '60286'
last_name: Sharapova
- first_name: Norbert
full_name: Lindlein, Norbert
last_name: Lindlein
- first_name: Maria
full_name: Chekhova, Maria
last_name: Chekhova
citation:
ama: Barakat I, Kalash M, Scharwald D, Sharapova P, Lindlein N, Chekhova M. Simultaneous
measurement of multimode squeezing through multimode phase-sensitive amplification.
Optica Quantum. 2025;3(1). doi:10.1364/opticaq.524682
apa: Barakat, I., Kalash, M., Scharwald, D., Sharapova, P., Lindlein, N., &
Chekhova, M. (2025). Simultaneous measurement of multimode squeezing through multimode
phase-sensitive amplification. Optica Quantum, 3(1), Article 36.
https://doi.org/10.1364/opticaq.524682
bibtex: '@article{Barakat_Kalash_Scharwald_Sharapova_Lindlein_Chekhova_2025, title={Simultaneous
measurement of multimode squeezing through multimode phase-sensitive amplification},
volume={3}, DOI={10.1364/opticaq.524682},
number={136}, journal={Optica Quantum}, publisher={Optica Publishing Group}, author={Barakat,
Ismail and Kalash, Mahmoud and Scharwald, Dennis and Sharapova, Polina and Lindlein,
Norbert and Chekhova, Maria}, year={2025} }'
chicago: Barakat, Ismail, Mahmoud Kalash, Dennis Scharwald, Polina Sharapova, Norbert
Lindlein, and Maria Chekhova. “Simultaneous Measurement of Multimode Squeezing
through Multimode Phase-Sensitive Amplification.” Optica Quantum 3, no.
1 (2025). https://doi.org/10.1364/opticaq.524682.
ieee: 'I. Barakat, M. Kalash, D. Scharwald, P. Sharapova, N. Lindlein, and M. Chekhova,
“Simultaneous measurement of multimode squeezing through multimode phase-sensitive
amplification,” Optica Quantum, vol. 3, no. 1, Art. no. 36, 2025, doi:
10.1364/opticaq.524682.'
mla: Barakat, Ismail, et al. “Simultaneous Measurement of Multimode Squeezing through
Multimode Phase-Sensitive Amplification.” Optica Quantum, vol. 3, no. 1,
36, Optica Publishing Group, 2025, doi:10.1364/opticaq.524682.
short: I. Barakat, M. Kalash, D. Scharwald, P. Sharapova, N. Lindlein, M. Chekhova,
Optica Quantum 3 (2025).
date_created: 2026-01-26T15:57:13Z
date_updated: 2026-02-10T22:44:44Z
department:
- _id: '15'
- _id: '569'
- _id: '170'
- _id: '35'
- _id: '429'
doi: 10.1364/opticaq.524682
intvolume: ' 3'
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://opg.optica.org/opticaq/viewmedia.cfm?uri=opticaq-3-1-36&seq=0
oa: '1'
project:
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '56'
name: TRR 142 - Project Area C
- _id: '174'
name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen
Systemen: Eine theoretische Analyse'
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
publication: Optica Quantum
publication_identifier:
issn:
- 2837-6714
publication_status: published
publisher: Optica Publishing Group
status: public
title: Simultaneous measurement of multimode squeezing through multimode phase-sensitive
amplification
type: journal_article
user_id: '55907'
volume: 3
year: '2025'
...
---
_id: '61245'
article_number: '032404'
author:
- first_name: Franziska
full_name: Barkhausen, Franziska
id: '63631'
last_name: Barkhausen
- first_name: Laura
full_name: Ares Santos, Laura
last_name: Ares Santos
- first_name: Stefan
full_name: Schumacher, Stefan
id: '27271'
last_name: Schumacher
orcid: 0000-0003-4042-4951
- first_name: Jan
full_name: Sperling, Jan
id: '75127'
last_name: Sperling
orcid: 0000-0002-5844-3205
citation:
ama: 'Barkhausen F, Ares Santos L, Schumacher S, Sperling J. Entanglement between
dependent degrees of freedom: Quasiparticle correlations. Physical Review A.
2025;111(3). doi:10.1103/physreva.111.032404'
apa: 'Barkhausen, F., Ares Santos, L., Schumacher, S., & Sperling, J. (2025).
Entanglement between dependent degrees of freedom: Quasiparticle correlations.
Physical Review A, 111(3), Article 032404. https://doi.org/10.1103/physreva.111.032404'
bibtex: '@article{Barkhausen_Ares Santos_Schumacher_Sperling_2025, title={Entanglement
between dependent degrees of freedom: Quasiparticle correlations}, volume={111},
DOI={10.1103/physreva.111.032404},
number={3032404}, journal={Physical Review A}, publisher={American Physical Society
(APS)}, author={Barkhausen, Franziska and Ares Santos, Laura and Schumacher, Stefan
and Sperling, Jan}, year={2025} }'
chicago: 'Barkhausen, Franziska, Laura Ares Santos, Stefan Schumacher, and Jan Sperling.
“Entanglement between Dependent Degrees of Freedom: Quasiparticle Correlations.”
Physical Review A 111, no. 3 (2025). https://doi.org/10.1103/physreva.111.032404.'
ieee: 'F. Barkhausen, L. Ares Santos, S. Schumacher, and J. Sperling, “Entanglement
between dependent degrees of freedom: Quasiparticle correlations,” Physical
Review A, vol. 111, no. 3, Art. no. 032404, 2025, doi: 10.1103/physreva.111.032404.'
mla: 'Barkhausen, Franziska, et al. “Entanglement between Dependent Degrees of Freedom:
Quasiparticle Correlations.” Physical Review A, vol. 111, no. 3, 032404,
American Physical Society (APS), 2025, doi:10.1103/physreva.111.032404.'
short: F. Barkhausen, L. Ares Santos, S. Schumacher, J. Sperling, Physical Review
A 111 (2025).
date_created: 2025-09-12T10:37:34Z
date_updated: 2025-09-12T10:42:16Z
department:
- _id: '15'
- _id: '170'
- _id: '297'
- _id: '706'
- _id: '35'
- _id: '230'
- _id: '623'
- _id: '429'
doi: 10.1103/physreva.111.032404
intvolume: ' 111'
issue: '3'
language:
- iso: eng
project:
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '54'
name: TRR 142 - Project Area A
- _id: '56'
name: TRR 142 - Project Area C
- _id: '61'
name: 'TRR 142; TP A04: Nichtlineare Quantenprozesstomographie und Photonik mit
Polaritonen in Mikrokavitäten'
- _id: '174'
name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen
Systemen: Eine theoretische Analyse'
- _id: '266'
name: 'PhoQC: Photonisches Quantencomputing'
publication: Physical Review A
publication_identifier:
issn:
- 2469-9926
- 2469-9934
publication_status: published
publisher: American Physical Society (APS)
status: public
title: 'Entanglement between dependent degrees of freedom: Quasiparticle correlations'
type: journal_article
user_id: '16199'
volume: 111
year: '2025'
...
---
_id: '61351'
abstract:
- lang: eng
text: AbstractThe interaction of water molecules
with semiconductor surfaces is relevant to various optoelectronic phenomena and
physicochemical processes. Despite advances in fundamental understanding of water‐exposed
surfaces, the detailed time‐ and energy‐resolved behavior of excited electrons
remains largely unexplored. Here, the effects of water exposure on the near‐surface
electron dynamics of phosphorus‐terminated p(2×2)/c(4×2)‐reconstructed indium
phosphide (100) (P‐rich InP) are studied experimentally and matched to theoretical
calculations. The P‐rich InP surface, consisting of H‐passivated P‐dimers, serves
as a model for other P‐containing III‐V semiconductors such as gallium phosphide
(GaP) or aluminum indium phosphide (AlInP). Electron dynamics near the surface
are probed with femtosecond resolution using time‐resolved two‐photon photoemission
(tr‐2PPE), a pump‐probe spectroscopic technique. Pulsed water exposure preserves
electronic states and significantly increases lifetimes at the conduction band
minimum (CBM). Density‐functional theory (DFT) calculations attribute these findings
to suppression of surface vibrational modes in the top P‐layer by water exposure,
reducing electronic transition probabilities of near‐band‐gap surface states.
The results suggest that many near‐surface state lifetimes reported in ultra‐high
vacuum may change significantly upon electrolyte exposure. These states may thus
contribute more strongly to surface reactions than traditionally assumed. Demonstrating
this effect for the technologically relevant P‐rich InP surface opens new opportunities
in this underexplored area of surface electrochemistry.
article_number: e00463
author:
- first_name: Jonathan
full_name: Diederich, Jonathan
last_name: Diederich
- first_name: Agnieszka
full_name: Paszuk, Agnieszka
last_name: Paszuk
- first_name: Isaac Azahel
full_name: Ruiz Alvarado, Isaac Azahel
id: '79462'
last_name: Ruiz Alvarado
orcid: 0000-0002-4710-1170
- first_name: Marvin
full_name: Krenz, Marvin
last_name: Krenz
- first_name: Mohammad Amin
full_name: Zare Pour, Mohammad Amin
last_name: Zare Pour
- first_name: Diwakar Suresh
full_name: Babu, Diwakar Suresh
last_name: Babu
- first_name: Jennifer
full_name: Velazquez Rojas, Jennifer
last_name: Velazquez Rojas
- first_name: Christian
full_name: Höhn, Christian
last_name: Höhn
- first_name: Yuying
full_name: Gao, Yuying
last_name: Gao
- first_name: Klaus
full_name: Schwarzburg, Klaus
last_name: Schwarzburg
- first_name: David
full_name: Ostheimer, David
last_name: Ostheimer
- first_name: Rainer
full_name: Eichberger, Rainer
last_name: Eichberger
- first_name: Wolf Gero
full_name: Schmidt, Wolf Gero
id: '468'
last_name: Schmidt
orcid: 0000-0002-2717-5076
- first_name: Thomas
full_name: Hannappel, Thomas
last_name: Hannappel
- first_name: Roel van
full_name: de Krol, Roel van
last_name: de Krol
- first_name: Dennis
full_name: Friedrich, Dennis
last_name: Friedrich
citation:
ama: Diederich J, Paszuk A, Ruiz Alvarado IA, et al. Ultrafast Electron Dynamics
at the Water‐Modified InP(100) Surface. Advanced Materials Interfaces.
2025;12(16). doi:10.1002/admi.202500463
apa: Diederich, J., Paszuk, A., Ruiz Alvarado, I. A., Krenz, M., Zare Pour, M. A.,
Babu, D. S., Velazquez Rojas, J., Höhn, C., Gao, Y., Schwarzburg, K., Ostheimer,
D., Eichberger, R., Schmidt, W. G., Hannappel, T., de Krol, R. van, & Friedrich,
D. (2025). Ultrafast Electron Dynamics at the Water‐Modified InP(100) Surface.
Advanced Materials Interfaces, 12(16), Article e00463. https://doi.org/10.1002/admi.202500463
bibtex: '@article{Diederich_Paszuk_Ruiz Alvarado_Krenz_Zare Pour_Babu_Velazquez
Rojas_Höhn_Gao_Schwarzburg_et al._2025, title={Ultrafast Electron Dynamics at
the Water‐Modified InP(100) Surface}, volume={12}, DOI={10.1002/admi.202500463},
number={16e00463}, journal={Advanced Materials Interfaces}, publisher={Wiley},
author={Diederich, Jonathan and Paszuk, Agnieszka and Ruiz Alvarado, Isaac Azahel
and Krenz, Marvin and Zare Pour, Mohammad Amin and Babu, Diwakar Suresh and Velazquez
Rojas, Jennifer and Höhn, Christian and Gao, Yuying and Schwarzburg, Klaus and
et al.}, year={2025} }'
chicago: Diederich, Jonathan, Agnieszka Paszuk, Isaac Azahel Ruiz Alvarado, Marvin
Krenz, Mohammad Amin Zare Pour, Diwakar Suresh Babu, Jennifer Velazquez Rojas,
et al. “Ultrafast Electron Dynamics at the Water‐Modified InP(100) Surface.” Advanced
Materials Interfaces 12, no. 16 (2025). https://doi.org/10.1002/admi.202500463.
ieee: 'J. Diederich et al., “Ultrafast Electron Dynamics at the Water‐Modified
InP(100) Surface,” Advanced Materials Interfaces, vol. 12, no. 16, Art.
no. e00463, 2025, doi: 10.1002/admi.202500463.'
mla: Diederich, Jonathan, et al. “Ultrafast Electron Dynamics at the Water‐Modified
InP(100) Surface.” Advanced Materials Interfaces, vol. 12, no. 16, e00463,
Wiley, 2025, doi:10.1002/admi.202500463.
short: J. Diederich, A. Paszuk, I.A. Ruiz Alvarado, M. Krenz, M.A. Zare Pour, D.S.
Babu, J. Velazquez Rojas, C. Höhn, Y. Gao, K. Schwarzburg, D. Ostheimer, R. Eichberger,
W.G. Schmidt, T. Hannappel, R. van de Krol, D. Friedrich, Advanced Materials Interfaces
12 (2025).
date_created: 2025-09-18T11:03:16Z
date_updated: 2025-09-18T11:06:59Z
department:
- _id: '15'
- _id: '170'
- _id: '295'
- _id: '35'
- _id: '230'
- _id: '27'
- _id: '429'
doi: 10.1002/admi.202500463
intvolume: ' 12'
issue: '16'
language:
- iso: eng
project:
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '55'
name: TRR 142 - Project Area B
- _id: '168'
name: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat
(B07*)
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
publication: Advanced Materials Interfaces
publication_identifier:
issn:
- 2196-7350
- 2196-7350
publication_status: published
publisher: Wiley
status: public
title: Ultrafast Electron Dynamics at the Water‐Modified InP(100) Surface
type: journal_article
user_id: '16199'
volume: 12
year: '2025'
...
---
_id: '61356'
abstract:
- lang: eng
text: First-principles calculations reveal how topological defects in semiconducting
carbon nanotubes trap triplet excitons and enable single-photon emission at telecom
wavelengths, offering new insights into their potential for photonic devices.
author:
- first_name: Timur
full_name: Biktagirov, Timur
id: '65612'
last_name: Biktagirov
- first_name: Uwe
full_name: Gerstmann, Uwe
id: '171'
last_name: Gerstmann
orcid: 0000-0002-4476-223X
- first_name: Wolf Gero
full_name: Schmidt, Wolf Gero
id: '468'
last_name: Schmidt
orcid: 0000-0002-2717-5076
citation:
ama: Biktagirov T, Gerstmann U, Schmidt WG. Topological defects in semiconducting
carbon nanotubes as triplet exciton traps and single-photon emitters. Nanoscale.
2025;17(11):6884-6891. doi:10.1039/d4nr03904a
apa: Biktagirov, T., Gerstmann, U., & Schmidt, W. G. (2025). Topological defects
in semiconducting carbon nanotubes as triplet exciton traps and single-photon
emitters. Nanoscale, 17(11), 6884–6891. https://doi.org/10.1039/d4nr03904a
bibtex: '@article{Biktagirov_Gerstmann_Schmidt_2025, title={Topological defects
in semiconducting carbon nanotubes as triplet exciton traps and single-photon
emitters}, volume={17}, DOI={10.1039/d4nr03904a},
number={11}, journal={Nanoscale}, publisher={Royal Society of Chemistry (RSC)},
author={Biktagirov, Timur and Gerstmann, Uwe and Schmidt, Wolf Gero}, year={2025},
pages={6884–6891} }'
chicago: 'Biktagirov, Timur, Uwe Gerstmann, and Wolf Gero Schmidt. “Topological
Defects in Semiconducting Carbon Nanotubes as Triplet Exciton Traps and Single-Photon
Emitters.” Nanoscale 17, no. 11 (2025): 6884–91. https://doi.org/10.1039/d4nr03904a.'
ieee: 'T. Biktagirov, U. Gerstmann, and W. G. Schmidt, “Topological defects in semiconducting
carbon nanotubes as triplet exciton traps and single-photon emitters,” Nanoscale,
vol. 17, no. 11, pp. 6884–6891, 2025, doi: 10.1039/d4nr03904a.'
mla: Biktagirov, Timur, et al. “Topological Defects in Semiconducting Carbon Nanotubes
as Triplet Exciton Traps and Single-Photon Emitters.” Nanoscale, vol. 17,
no. 11, Royal Society of Chemistry (RSC), 2025, pp. 6884–91, doi:10.1039/d4nr03904a.
short: T. Biktagirov, U. Gerstmann, W.G. Schmidt, Nanoscale 17 (2025) 6884–6891.
date_created: 2025-09-18T11:23:25Z
date_updated: 2025-09-18T11:26:23Z
department:
- _id: '15'
- _id: '170'
- _id: '295'
- _id: '790'
- _id: '35'
- _id: '230'
- _id: '27'
- _id: '429'
doi: 10.1039/d4nr03904a
intvolume: ' 17'
issue: '11'
language:
- iso: eng
page: 6884-6891
project:
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '54'
name: TRR 142 - Project Area A
- _id: '55'
name: TRR 142 - Project Area B
- _id: '168'
name: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat
(B07*)
- _id: '166'
name: TRR 142 - Subproject A11
publication: Nanoscale
publication_identifier:
issn:
- 2040-3364
- 2040-3372
publication_status: published
publisher: Royal Society of Chemistry (RSC)
status: public
title: Topological defects in semiconducting carbon nanotubes as triplet exciton traps
and single-photon emitters
type: journal_article
user_id: '16199'
volume: 17
year: '2025'
...
---
_id: '60891'
abstract:
- lang: eng
text: Straight dielectric waveguide channels made from slabs of thin-film lithium
niobate (TFLN), or lithium niobate on insulator (LNOI), are investigated in the
linear regime, for channels of rib and strip type with common trapezoidal cross
sections, in Z-cut and X-cut samples at varying on-chip orientation. We clarify
the theoretical basis for the waveguides with potentially non-diagonal core permittivity.
Symmetry classes can be distinguished that differ in their consequences for potential
modal degeneracy and polarization conversion. Our rigorous numerical analysis
by means of a finite-element solver takes the anisotropy of the lithium niobate
cores rigorously into account. We discuss extensive data for effective indices,
polarization properties, and hybridization of guided modes, in single- and multimode
channels. Scans over the waveguide width and orientation as primary parameters
are complemented by a series of illustrations of vectorial mode profiles. These
turn out to be essentially complex in cases of X-cut channels at non-crystal-axis-aligned
orientations.
author:
- first_name: Manfred
full_name: Hammer, Manfred
id: '48077'
last_name: Hammer
orcid: 0000-0002-6331-9348
- first_name: Shahriar
full_name: Khan, Shahriar
last_name: Khan
- first_name: Behnood
full_name: Taheri, Behnood
last_name: Taheri
- first_name: Henna
full_name: Farheen, Henna
id: '53444'
last_name: Farheen
orcid: 0000-0001-7730-3489
- first_name: Jens
full_name: Förstner, Jens
id: '158'
last_name: Förstner
orcid: 0000-0001-7059-9862
citation:
ama: 'Hammer M, Khan S, Taheri B, Farheen H, Förstner J. TFLN channel waveguides
of rib and strip type: Properties of guided modes. Optics Continuum. 2025;4(10):2356.
doi:10.1364/optcon.569959'
apa: 'Hammer, M., Khan, S., Taheri, B., Farheen, H., & Förstner, J. (2025).
TFLN channel waveguides of rib and strip type: Properties of guided modes. Optics
Continuum, 4(10), 2356. https://doi.org/10.1364/optcon.569959'
bibtex: '@article{Hammer_Khan_Taheri_Farheen_Förstner_2025, title={TFLN channel
waveguides of rib and strip type: Properties of guided modes}, volume={4}, DOI={10.1364/optcon.569959}, number={10},
journal={Optics Continuum}, publisher={Optica Publishing Group}, author={Hammer,
Manfred and Khan, Shahriar and Taheri, Behnood and Farheen, Henna and Förstner,
Jens}, year={2025}, pages={2356} }'
chicago: 'Hammer, Manfred, Shahriar Khan, Behnood Taheri, Henna Farheen, and Jens
Förstner. “TFLN Channel Waveguides of Rib and Strip Type: Properties of Guided
Modes.” Optics Continuum 4, no. 10 (2025): 2356. https://doi.org/10.1364/optcon.569959.'
ieee: 'M. Hammer, S. Khan, B. Taheri, H. Farheen, and J. Förstner, “TFLN channel
waveguides of rib and strip type: Properties of guided modes,” Optics Continuum,
vol. 4, no. 10, p. 2356, 2025, doi: 10.1364/optcon.569959.'
mla: 'Hammer, Manfred, et al. “TFLN Channel Waveguides of Rib and Strip Type: Properties
of Guided Modes.” Optics Continuum, vol. 4, no. 10, Optica Publishing Group,
2025, p. 2356, doi:10.1364/optcon.569959.'
short: M. Hammer, S. Khan, B. Taheri, H. Farheen, J. Förstner, Optics Continuum
4 (2025) 2356.
date_created: 2025-08-06T09:36:30Z
date_updated: 2025-10-05T11:52:55Z
ddc:
- '530'
department:
- _id: '61'
- _id: '230'
- _id: '429'
- _id: '623'
doi: 10.1364/optcon.569959
file:
- access_level: closed
content_type: application/pdf
creator: fossie
date_created: 2025-10-05T11:48:25Z
date_updated: 2025-10-05T11:48:25Z
file_id: '61516'
file_name: 2025-08 Hammer - Optics Continuum - TFLN channel waveguides of rib and
strip type. Properties of guided modes (official version).pdf
file_size: 5417636
relation: main_file
success: 1
file_date_updated: 2025-10-05T11:48:25Z
has_accepted_license: '1'
intvolume: ' 4'
issue: '10'
keyword:
- tet_topic_waveguide
language:
- iso: eng
page: '2356'
publication: Optics Continuum
publication_identifier:
issn:
- 2770-0208
publication_status: published
publisher: Optica Publishing Group
status: public
title: 'TFLN channel waveguides of rib and strip type: Properties of guided modes'
type: journal_article
user_id: '158'
volume: 4
year: '2025'
...
---
_id: '61760'
abstract:
- lang: eng
text: We present a topology-optimized silicon nitride (Si3N4) coupler designed to
enhance the coupling efficiency between integrated single-photon emitters and
photonic waveguide modes. By leveraging inverse design techniques, we optimize
the coupler’s geometry to maximize power transfer while maintaining fabrication
feasibility by improving mode overlap and directional emission, addressing the
challenge of low coupling efficiency caused by size mismatch and material incompatibility.
Simulations demonstrate a substantial enhancement in photon extraction and waveguide
coupling. This approach can be extended to other photonic devices, offering a
versatile framework for improving quantum light-matter interactions in integrated
photonics.
author:
- first_name: Henna
full_name: Farheen, Henna
id: '53444'
last_name: Farheen
orcid: 0000-0001-7730-3489
- first_name: Yuheng
full_name: Chen, Yuheng
last_name: Chen
- first_name: Peigang
full_name: Chen, Peigang
last_name: Chen
- first_name: Artem
full_name: Kryvobok, Artem
last_name: Kryvobok
- first_name: Samuel
full_name: Peana, Samuel
last_name: Peana
- first_name: Alexander
full_name: Senichev, Alexander
last_name: Senichev
- first_name: Vladimir M.
full_name: Shalaev, Vladimir M.
last_name: Shalaev
- first_name: Alexandra
full_name: Boltasseva, Alexandra
last_name: Boltasseva
- first_name: Jens
full_name: Förstner, Jens
id: '158'
last_name: Förstner
orcid: 0000-0001-7059-9862
- first_name: Alexander V.
full_name: Kildishev, Alexander V.
last_name: Kildishev
citation:
ama: 'Farheen H, Chen Y, Chen P, et al. Topology-optimized silicon nitride coupler
for integrated single-photon emitters. In: Ni X, Cai W, eds. Photonic Computing:
From Materials and Devices to Systems and Applications II. SPIE; 2025. doi:10.1117/12.3065734'
apa: 'Farheen, H., Chen, Y., Chen, P., Kryvobok, A., Peana, S., Senichev, A., Shalaev,
V. M., Boltasseva, A., Förstner, J., & Kildishev, A. V. (2025). Topology-optimized
silicon nitride coupler for integrated single-photon emitters. In X. Ni &
W. Cai (Eds.), Photonic Computing: From Materials and Devices to Systems and
Applications II. SPIE. https://doi.org/10.1117/12.3065734'
bibtex: '@inproceedings{Farheen_Chen_Chen_Kryvobok_Peana_Senichev_Shalaev_Boltasseva_Förstner_Kildishev_2025,
title={Topology-optimized silicon nitride coupler for integrated single-photon
emitters}, DOI={10.1117/12.3065734},
booktitle={Photonic Computing: From Materials and Devices to Systems and Applications
II}, publisher={SPIE}, author={Farheen, Henna and Chen, Yuheng and Chen, Peigang
and Kryvobok, Artem and Peana, Samuel and Senichev, Alexander and Shalaev, Vladimir
M. and Boltasseva, Alexandra and Förstner, Jens and Kildishev, Alexander V.},
editor={Ni, Xingjie and Cai, Wenshan}, year={2025} }'
chicago: 'Farheen, Henna, Yuheng Chen, Peigang Chen, Artem Kryvobok, Samuel Peana,
Alexander Senichev, Vladimir M. Shalaev, Alexandra Boltasseva, Jens Förstner,
and Alexander V. Kildishev. “Topology-Optimized Silicon Nitride Coupler for Integrated
Single-Photon Emitters.” In Photonic Computing: From Materials and Devices
to Systems and Applications II, edited by Xingjie Ni and Wenshan Cai. SPIE,
2025. https://doi.org/10.1117/12.3065734.'
ieee: 'H. Farheen et al., “Topology-optimized silicon nitride coupler for
integrated single-photon emitters,” in Photonic Computing: From Materials and
Devices to Systems and Applications II, 2025, doi: 10.1117/12.3065734.'
mla: 'Farheen, Henna, et al. “Topology-Optimized Silicon Nitride Coupler for Integrated
Single-Photon Emitters.” Photonic Computing: From Materials and Devices to
Systems and Applications II, edited by Xingjie Ni and Wenshan Cai, SPIE, 2025,
doi:10.1117/12.3065734.'
short: 'H. Farheen, Y. Chen, P. Chen, A. Kryvobok, S. Peana, A. Senichev, V.M. Shalaev,
A. Boltasseva, J. Förstner, A.V. Kildishev, in: X. Ni, W. Cai (Eds.), Photonic
Computing: From Materials and Devices to Systems and Applications II, SPIE, 2025.'
date_created: 2025-10-08T15:20:13Z
date_updated: 2025-10-08T15:22:30Z
department:
- _id: '61'
- _id: '230'
- _id: '429'
- _id: '623'
doi: 10.1117/12.3065734
editor:
- first_name: Xingjie
full_name: Ni, Xingjie
last_name: Ni
- first_name: Wenshan
full_name: Cai, Wenshan
last_name: Cai
keyword:
- tet_topic_waveguide
language:
- iso: eng
publication: 'Photonic Computing: From Materials and Devices to Systems and Applications
II'
publication_status: published
publisher: SPIE
status: public
title: Topology-optimized silicon nitride coupler for integrated single-photon emitters
type: conference
user_id: '158'
year: '2025'
...
---
_id: '62911'
abstract:
- lang: eng
text: In this paper, we theoretically study the spectral and temporal properties
of pulsed spontaneous parametric down-conversion (SPDC) generated in lossy waveguides.
Our theoretical approach is based on the formalism of Gaussian states and the
Langevin equation, which is elaborated for weak parametric down-conversion and
photon-number-unresolved click detection. Using the example of frequency-degenerate
type-II SPDC generated under the pump-idler group-velocity-matching condition,
we show how the joint-spectral intensity, mode structure, normalized second-order
correlation function, and Hong-Ou-Mandel interference pattern depend on internal
losses of the SPDC process. We found that the joint-spectral intensity is almost
insensitive to internal losses, while the second-order correlation function shows
a strong dependence on them, being different for the signal and idler beams in
the presence of internal losses. Based on the sensitivity of the normalized second-order
correlation function, we show how its measurement can be used to experimentally
determine internal losses.
article_number: '033122'
author:
- first_name: Denis A.
full_name: Kopylov, Denis A.
last_name: Kopylov
- first_name: Michael
full_name: Stefszky, Michael
id: '42777'
last_name: Stefszky
- first_name: Torsten
full_name: Meier, Torsten
id: '344'
last_name: Meier
orcid: 0000-0001-8864-2072
- first_name: Christine
full_name: Silberhorn, Christine
id: '26263'
last_name: Silberhorn
- first_name: Polina R.
full_name: Sharapova, Polina R.
id: '60286'
last_name: Sharapova
citation:
ama: 'Kopylov DA, Stefszky M, Meier T, Silberhorn C, Sharapova PR. Spectral and
temporal properties of type-II parametric down-conversion: The impact of losses
during state generation. Physical Review Research. 2025;7(3). doi:10.1103/zp72-7qwl'
apa: 'Kopylov, D. A., Stefszky, M., Meier, T., Silberhorn, C., & Sharapova,
P. R. (2025). Spectral and temporal properties of type-II parametric down-conversion:
The impact of losses during state generation. Physical Review Research,
7(3), Article 033122. https://doi.org/10.1103/zp72-7qwl'
bibtex: '@article{Kopylov_Stefszky_Meier_Silberhorn_Sharapova_2025, title={Spectral
and temporal properties of type-II parametric down-conversion: The impact of losses
during state generation}, volume={7}, DOI={10.1103/zp72-7qwl},
number={3033122}, journal={Physical Review Research}, publisher={American Physical
Society (APS)}, author={Kopylov, Denis A. and Stefszky, Michael and Meier, Torsten
and Silberhorn, Christine and Sharapova, Polina R.}, year={2025} }'
chicago: 'Kopylov, Denis A., Michael Stefszky, Torsten Meier, Christine Silberhorn,
and Polina R. Sharapova. “Spectral and Temporal Properties of Type-II Parametric
down-Conversion: The Impact of Losses during State Generation.” Physical Review
Research 7, no. 3 (2025). https://doi.org/10.1103/zp72-7qwl.'
ieee: 'D. A. Kopylov, M. Stefszky, T. Meier, C. Silberhorn, and P. R. Sharapova,
“Spectral and temporal properties of type-II parametric down-conversion: The impact
of losses during state generation,” Physical Review Research, vol. 7, no.
3, Art. no. 033122, 2025, doi: 10.1103/zp72-7qwl.'
mla: 'Kopylov, Denis A., et al. “Spectral and Temporal Properties of Type-II Parametric
down-Conversion: The Impact of Losses during State Generation.” Physical Review
Research, vol. 7, no. 3, 033122, American Physical Society (APS), 2025, doi:10.1103/zp72-7qwl.'
short: D.A. Kopylov, M. Stefszky, T. Meier, C. Silberhorn, P.R. Sharapova, Physical
Review Research 7 (2025).
date_created: 2025-12-05T09:33:36Z
date_updated: 2025-12-05T09:55:22Z
department:
- _id: '15'
- _id: '569'
- _id: '170'
- _id: '293'
- _id: '288'
- _id: '230'
- _id: '623'
- _id: '429'
- _id: '35'
doi: 10.1103/zp72-7qwl
intvolume: ' 7'
issue: '3'
language:
- iso: eng
project:
- _id: '266'
name: 'PhoQC: Photonisches Quantencomputing'
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '56'
name: TRR 142 - Project Area C
- _id: '174'
name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen
Systemen: Eine theoretische Analyse'
publication: Physical Review Research
publication_identifier:
issn:
- 2643-1564
publication_status: published
publisher: American Physical Society (APS)
status: public
title: 'Spectral and temporal properties of type-II parametric down-conversion: The
impact of losses during state generation'
type: journal_article
user_id: '16199'
volume: 7
year: '2025'
...
---
_id: '60568'
article_number: '122776'
author:
- first_name: Adriana
full_name: Bocchini, Adriana
id: '58349'
last_name: Bocchini
orcid: 0000-0002-2134-3075
- first_name: S.
full_name: Kollmann, S.
last_name: Kollmann
- first_name: Uwe
full_name: Gerstmann, Uwe
id: '171'
last_name: Gerstmann
orcid: 0000-0002-4476-223X
- first_name: Wolf Gero
full_name: Schmidt, Wolf Gero
id: '468'
last_name: Schmidt
orcid: 0000-0002-2717-5076
- first_name: Guido
full_name: Grundmeier, Guido
id: '194'
last_name: Grundmeier
citation:
ama: Bocchini A, Kollmann S, Gerstmann U, Schmidt WG, Grundmeier G. Phosphonic acid
adsorption on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si23.svg"
display="inline" id="d1e564"><mml:mi>α</mml:mi></mml:math>-Bi<mml:math
xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si24.svg" display="inline"
id="d1e569"><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math>O<mml:math
xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si25.svg" display="inline"
id="d1e577"><mml:msub><mml:mrow/><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:math>
surfaces. Surface Science. 2025;760. doi:10.1016/j.susc.2025.122776
apa: Bocchini, A., Kollmann, S., Gerstmann, U., Schmidt, W. G., & Grundmeier,
G. (2025). Phosphonic acid adsorption on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"
altimg="si23.svg" display="inline" id="d1e564"><mml:mi>α</mml:mi></mml:math>-Bi<mml:math
xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si24.svg" display="inline"
id="d1e569"><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math>O<mml:math
xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si25.svg" display="inline"
id="d1e577"><mml:msub><mml:mrow/><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:math>
surfaces. Surface Science, 760, Article 122776. https://doi.org/10.1016/j.susc.2025.122776
bibtex: '@article{Bocchini_Kollmann_Gerstmann_Schmidt_Grundmeier_2025, title={Phosphonic
acid adsorption on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"
altimg="si23.svg" display="inline" id="d1e564"><mml:mi>α</mml:mi></mml:math>-Bi<mml:math
xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si24.svg" display="inline"
id="d1e569"><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math>O<mml:math
xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si25.svg" display="inline"
id="d1e577"><mml:msub><mml:mrow/><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:math>
surfaces}, volume={760}, DOI={10.1016/j.susc.2025.122776},
number={122776}, journal={Surface Science}, publisher={Elsevier BV}, author={Bocchini,
Adriana and Kollmann, S. and Gerstmann, Uwe and Schmidt, Wolf Gero and Grundmeier,
Guido}, year={2025} }'
chicago: Bocchini, Adriana, S. Kollmann, Uwe Gerstmann, Wolf Gero Schmidt, and Guido
Grundmeier. “Phosphonic Acid Adsorption on <mml:Math Xmlns:Mml="http://Www.W3.Org/1998/Math/MathML"
Altimg="si23.Svg" Display="inline" Id="d1e564"><mml:Mi>α</Mml:Mi></Mml:Math>-Bi<mml:Math
Xmlns:Mml="http://Www.W3.Org/1998/Math/MathML" Altimg="si24.Svg" Display="inline"
Id="d1e569"><mml:Msub><mml:Mrow/><mml:Mrow><mml:Mn>2</Mml:Mn></Mml:Mrow></Mml:Msub></Mml:Math>O<mml:Math
Xmlns:Mml="http://Www.W3.Org/1998/Math/MathML" Altimg="si25.Svg" Display="inline"
Id="d1e577"><mml:Msub><mml:Mrow/><mml:Mrow><mml:Mn>3</Mml:Mn></Mml:Mrow></Mml:Msub></Mml:Math>
Surfaces.” Surface Science 760 (2025). https://doi.org/10.1016/j.susc.2025.122776.
ieee: 'A. Bocchini, S. Kollmann, U. Gerstmann, W. G. Schmidt, and G. Grundmeier,
“Phosphonic acid adsorption on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"
altimg="si23.svg" display="inline" id="d1e564"><mml:mi>α</mml:mi></mml:math>-Bi<mml:math
xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si24.svg" display="inline"
id="d1e569"><mml:msub><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math>O<mml:math
xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si25.svg" display="inline"
id="d1e577"><mml:msub><mml:mrow/><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:math>
surfaces,” Surface Science, vol. 760, Art. no. 122776, 2025, doi: 10.1016/j.susc.2025.122776.'
mla: Bocchini, Adriana, et al. “Phosphonic Acid Adsorption on <mml:Math Xmlns:Mml="http://Www.W3.Org/1998/Math/MathML"
Altimg="si23.Svg" Display="inline" Id="d1e564"><mml:Mi>α</Mml:Mi></Mml:Math>-Bi<mml:Math
Xmlns:Mml="http://Www.W3.Org/1998/Math/MathML" Altimg="si24.Svg" Display="inline"
Id="d1e569"><mml:Msub><mml:Mrow/><mml:Mrow><mml:Mn>2</Mml:Mn></Mml:Mrow></Mml:Msub></Mml:Math>O<mml:Math
Xmlns:Mml="http://Www.W3.Org/1998/Math/MathML" Altimg="si25.Svg" Display="inline"
Id="d1e577"><mml:Msub><mml:Mrow/><mml:Mrow><mml:Mn>3</Mml:Mn></Mml:Mrow></Mml:Msub></Mml:Math>
Surfaces.” Surface Science, vol. 760, 122776, Elsevier BV, 2025, doi:10.1016/j.susc.2025.122776.
short: A. Bocchini, S. Kollmann, U. Gerstmann, W.G. Schmidt, G. Grundmeier, Surface
Science 760 (2025).
date_created: 2025-07-09T09:23:04Z
date_updated: 2025-12-05T13:34:10Z
department:
- _id: '15'
- _id: '2'
- _id: '230'
- _id: '295'
- _id: '790'
- _id: '302'
- _id: '429'
- _id: '35'
- _id: '170'
- _id: '27'
doi: 10.1016/j.susc.2025.122776
intvolume: ' 760'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1016/j.susc.2025.122776
oa: '1'
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
- _id: '53'
name: 'TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden
Konzepten zu funktionellen Strukturen'
- _id: '55'
name: 'TRR 142 - B: TRR 142 - Project Area B'
- _id: '54'
name: 'TRR 142 - A: TRR 142 - Project Area A'
- _id: '168'
name: 'TRR 142 - B07: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften
von Lithiumniobat (B07*)'
- _id: '166'
name: 'TRR 142 - A11: TRR 142 - Subproject A11'
publication: Surface Science
publication_identifier:
issn:
- 0039-6028
publication_status: published
publisher: Elsevier BV
status: public
title: Phosphonic acid adsorption on α-Bi2O3
surfaces
type: journal_article
user_id: '16199'
volume: 760
year: '2025'
...
---
_id: '61353'
abstract:
- lang: eng
text: "Abstract\r\n Muonic hydrogen
is an exotic atom where a muon instead of an electron is bound to a proton. The
comparably high mass of the muon (≈ 207 · me\r\n
\ ) has two important effects, (i) the reduced mass
of the system becomes more important, and (ii) the muon is localized much closer
to the nucleus. Thus, muonic hydrogen is not only excellently suitable for evaluating
highly precise quantum electrodynamic (QED) calculations, but may also be used
for assessing new approaches including finite nuclear size (FNS) effects to evaluate
the proton structure and improve calculation schemes for the hyperfine splittings
of many-particle systems, as e.g. to be implemented in density functional theory
(DFT) software packages. Here, starting from Dirac’s equation we calculate the
relativistic hyperfine splitting of the ground state and several excited states
of muonic hydrogen analytically for different charge and magnetization models.
The FNS related hyperfine shifts are compared with the differences between QED
calculations and experimental measurements. This comparison also allows to unravel
the role of the reduced mass, which is on one hand crucial in case of muonic atoms,
but on the other hand is by no means well defined in relativistic quantum mechanics."
article_number: '012001'
author:
- first_name: Katharina L.
full_name: Franzke, Katharina L.
last_name: Franzke
- first_name: Wolf Gero
full_name: Schmidt, Wolf Gero
id: '468'
last_name: Schmidt
orcid: 0000-0002-2717-5076
- first_name: Uwe
full_name: Gerstmann, Uwe
id: '171'
last_name: Gerstmann
orcid: 0000-0002-4476-223X
citation:
ama: 'Franzke KL, Schmidt WG, Gerstmann U. Finite-size and relativistic effects
onto hyperfine interaction of muonic hydrogen. Journal of Physics: Conference
Series. 2025;3027(1). doi:10.1088/1742-6596/3027/1/012001'
apa: 'Franzke, K. L., Schmidt, W. G., & Gerstmann, U. (2025). Finite-size and
relativistic effects onto hyperfine interaction of muonic hydrogen. Journal
of Physics: Conference Series, 3027(1), Article 012001. https://doi.org/10.1088/1742-6596/3027/1/012001'
bibtex: '@article{Franzke_Schmidt_Gerstmann_2025, title={Finite-size and relativistic
effects onto hyperfine interaction of muonic hydrogen}, volume={3027}, DOI={10.1088/1742-6596/3027/1/012001},
number={1012001}, journal={Journal of Physics: Conference Series}, publisher={IOP
Publishing}, author={Franzke, Katharina L. and Schmidt, Wolf Gero and Gerstmann,
Uwe}, year={2025} }'
chicago: 'Franzke, Katharina L., Wolf Gero Schmidt, and Uwe Gerstmann. “Finite-Size
and Relativistic Effects onto Hyperfine Interaction of Muonic Hydrogen.” Journal
of Physics: Conference Series 3027, no. 1 (2025). https://doi.org/10.1088/1742-6596/3027/1/012001.'
ieee: 'K. L. Franzke, W. G. Schmidt, and U. Gerstmann, “Finite-size and relativistic
effects onto hyperfine interaction of muonic hydrogen,” Journal of Physics:
Conference Series, vol. 3027, no. 1, Art. no. 012001, 2025, doi: 10.1088/1742-6596/3027/1/012001.'
mla: 'Franzke, Katharina L., et al. “Finite-Size and Relativistic Effects onto Hyperfine
Interaction of Muonic Hydrogen.” Journal of Physics: Conference Series,
vol. 3027, no. 1, 012001, IOP Publishing, 2025, doi:10.1088/1742-6596/3027/1/012001.'
short: 'K.L. Franzke, W.G. Schmidt, U. Gerstmann, Journal of Physics: Conference
Series 3027 (2025).'
date_created: 2025-09-18T11:17:05Z
date_updated: 2025-12-05T13:32:45Z
department:
- _id: '15'
- _id: '170'
- _id: '295'
- _id: '35'
- _id: '230'
- _id: '429'
- _id: '27'
- _id: '790'
doi: 10.1088/1742-6596/3027/1/012001
intvolume: ' 3027'
issue: '1'
language:
- iso: eng
project:
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '54'
name: TRR 142 - Project Area A
- _id: '166'
name: TRR 142 - Subproject A11
publication: 'Journal of Physics: Conference Series'
publication_identifier:
issn:
- 1742-6588
- 1742-6596
publication_status: published
publisher: IOP Publishing
status: public
title: Finite-size and relativistic effects onto hyperfine interaction of muonic hydrogen
type: journal_article
user_id: '16199'
volume: 3027
year: '2025'
...
---
_id: '60992'
abstract:
- lang: eng
text: Non-Hermitian systems hosting exceptional points (EPs) exhibit enhanced sensitivity
and unconventional mode dynamics. Going beyond isolated EPs, here we report on
the existence of exceptional rings (ERs) in planar optical resonators with specific
form of circular dichroism and TE-TM splitting. Such exceptional rings possess
intriguing topologies as discussed earlier for condensed matter systems, but they
remain virtually unexplored in presence of nonlinearity, for which our photonic
platform is ideal. We find that when Kerr-type nonlinearity (or saturable gain)
is introduced, the linear ER splits into two concentric ERs, with the larger-radius
ring being a ring of third-order EPs. Transitioning from linear to nonlinear regime,
we present a rigorous analysis of spectral topology and report enhanced and adjustable
perturbation response in the nonlinear regime. Whereas certain features are specific
to our system, the results on non-Hermitian spectral topology and nonlinearity-enhanced
perturbation response are generic and equally relevant to a broad class of other
nonlinear non-Hermitian systems, providing a universal framework for engineering
ERs and EPs in nonlinear non-Hermitian systems.
author:
- first_name: Jan
full_name: Wingenbach, Jan
id: '69187'
last_name: Wingenbach
- first_name: 'Laura '
full_name: 'Ares Santos, Laura '
last_name: Ares Santos
- first_name: Xuekai
full_name: Ma, Xuekai
id: '59416'
last_name: Ma
- first_name: Jan
full_name: Sperling, Jan
id: '75127'
last_name: Sperling
orcid: 0000-0002-5844-3205
- first_name: Stefan
full_name: Schumacher, Stefan
id: '27271'
last_name: Schumacher
orcid: 0000-0003-4042-4951
citation:
ama: Wingenbach J, Ares Santos L, Ma X, Sperling J, Schumacher S. Sensitivity and
Topology of Exceptional Rings in Nonlinear Non-Hermitian Planar Optical Microcavities.
Arxiv. Published online 2025. doi:10.48550/ARXIV.2507.07099
apa: Wingenbach, J., Ares Santos, L., Ma, X., Sperling, J., & Schumacher, S.
(2025). Sensitivity and Topology of Exceptional Rings in Nonlinear Non-Hermitian
Planar Optical Microcavities. Arxiv. https://doi.org/10.48550/ARXIV.2507.07099
bibtex: '@article{Wingenbach_Ares Santos_Ma_Sperling_Schumacher_2025, title={Sensitivity
and Topology of Exceptional Rings in Nonlinear Non-Hermitian Planar Optical Microcavities},
DOI={10.48550/ARXIV.2507.07099},
journal={Arxiv}, publisher={Arxiv}, author={Wingenbach, Jan and Ares Santos, Laura and
Ma, Xuekai and Sperling, Jan and Schumacher, Stefan}, year={2025} }'
chicago: Wingenbach, Jan, Laura Ares Santos, Xuekai Ma, Jan Sperling, and Stefan
Schumacher. “Sensitivity and Topology of Exceptional Rings in Nonlinear Non-Hermitian
Planar Optical Microcavities.” Arxiv, 2025. https://doi.org/10.48550/ARXIV.2507.07099.
ieee: 'J. Wingenbach, L. Ares Santos, X. Ma, J. Sperling, and S. Schumacher, “Sensitivity
and Topology of Exceptional Rings in Nonlinear Non-Hermitian Planar Optical Microcavities,”
Arxiv, 2025, doi: 10.48550/ARXIV.2507.07099.'
mla: Wingenbach, Jan, et al. “Sensitivity and Topology of Exceptional Rings in Nonlinear
Non-Hermitian Planar Optical Microcavities.” Arxiv, Arxiv, 2025, doi:10.48550/ARXIV.2507.07099.
short: J. Wingenbach, L. Ares Santos, X. Ma, J. Sperling, S. Schumacher, Arxiv (2025).
date_created: 2025-08-25T11:15:22Z
date_updated: 2025-12-05T13:55:48Z
department:
- _id: '15'
- _id: '170'
- _id: '297'
- _id: '706'
- _id: '705'
- _id: '35'
- _id: '230'
- _id: '429'
- _id: '27'
doi: 10.48550/ARXIV.2507.07099
language:
- iso: eng
project:
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '174'
name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen
Systemen: Eine theoretische Analyse'
- _id: '56'
name: TRR 142 - Project Area C
publication: Arxiv
publisher: Arxiv
status: public
title: Sensitivity and Topology of Exceptional Rings in Nonlinear Non-Hermitian Planar
Optical Microcavities
type: journal_article
user_id: '16199'
year: '2025'
...
---
_id: '62980'
abstract:
- lang: eng
text: We introduce a new classification of multimode states with a fixed
number of photons. This classification is based on the factorizability of homogeneous
multivariate polynomials and is invariant under unitary transformations. The classes
physically correspond to field excitations in terms of single and multiple photons,
each of which is in an arbitrary irreducible superposition of quantized modes.
We further show how the transitions between classes are rendered possible by photon
addition, photon subtraction, and photon-projection nonlinearities. We explicitly
put forward a design for a multilayer interferometer in which the states for different
classes can be generated with state-of-the-art experimental techniques. Limitations
of the proposed designs are analyzed using the introduced classification, providing
a benchmark for the robustness of certain states and classes.
article_number: '033062'
author:
- first_name: Denis A.
full_name: Kopylov, Denis A.
last_name: Kopylov
- first_name: Christian
full_name: Offen, Christian
id: '85279'
last_name: Offen
orcid: 0000-0002-5940-8057
- first_name: Laura
full_name: Ares, Laura
last_name: Ares
- first_name: Boris Edgar
full_name: Wembe Moafo, Boris Edgar
id: '95394'
last_name: Wembe Moafo
- first_name: Sina
full_name: Ober-Blöbaum, Sina
id: '16494'
last_name: Ober-Blöbaum
- first_name: Torsten
full_name: Meier, Torsten
id: '344'
last_name: Meier
orcid: 0000-0001-8864-2072
- first_name: Polina R.
full_name: Sharapova, Polina R.
id: '60286'
last_name: Sharapova
- first_name: Jan
full_name: Sperling, Jan
id: '75127'
last_name: Sperling
orcid: 0000-0002-5844-3205
citation:
ama: Kopylov DA, Offen C, Ares L, et al. Multiphoton, multimode state classification
for nonlinear optical circuits. Physical Review Research. 2025;7(3). doi:10.1103/sv6z-v1gk
apa: Kopylov, D. A., Offen, C., Ares, L., Wembe Moafo, B. E., Ober-Blöbaum, S.,
Meier, T., Sharapova, P. R., & Sperling, J. (2025). Multiphoton, multimode
state classification for nonlinear optical circuits. Physical Review Research,
7(3), Article 033062. https://doi.org/10.1103/sv6z-v1gk
bibtex: '@article{Kopylov_Offen_Ares_Wembe Moafo_Ober-Blöbaum_Meier_Sharapova_Sperling_2025,
title={Multiphoton, multimode state classification for nonlinear optical circuits},
volume={7}, DOI={10.1103/sv6z-v1gk},
number={3033062}, journal={Physical Review Research}, publisher={American Physical
Society (APS)}, author={Kopylov, Denis A. and Offen, Christian and Ares, Laura
and Wembe Moafo, Boris Edgar and Ober-Blöbaum, Sina and Meier, Torsten and Sharapova,
Polina R. and Sperling, Jan}, year={2025} }'
chicago: Kopylov, Denis A., Christian Offen, Laura Ares, Boris Edgar Wembe Moafo,
Sina Ober-Blöbaum, Torsten Meier, Polina R. Sharapova, and Jan Sperling. “Multiphoton,
Multimode State Classification for Nonlinear Optical Circuits.” Physical Review
Research 7, no. 3 (2025). https://doi.org/10.1103/sv6z-v1gk.
ieee: 'D. A. Kopylov et al., “Multiphoton, multimode state classification
for nonlinear optical circuits,” Physical Review Research, vol. 7, no.
3, Art. no. 033062, 2025, doi: 10.1103/sv6z-v1gk.'
mla: Kopylov, Denis A., et al. “Multiphoton, Multimode State Classification for
Nonlinear Optical Circuits.” Physical Review Research, vol. 7, no. 3, 033062,
American Physical Society (APS), 2025, doi:10.1103/sv6z-v1gk.
short: D.A. Kopylov, C. Offen, L. Ares, B.E. Wembe Moafo, S. Ober-Blöbaum, T. Meier,
P.R. Sharapova, J. Sperling, Physical Review Research 7 (2025).
date_created: 2025-12-09T09:08:39Z
date_updated: 2025-12-09T09:10:01Z
department:
- _id: '15'
- _id: '569'
- _id: '170'
- _id: '293'
- _id: '706'
- _id: '636'
- _id: '35'
- _id: '230'
- _id: '429'
- _id: '623'
doi: 10.1103/sv6z-v1gk
intvolume: ' 7'
issue: '3'
language:
- iso: eng
project:
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '56'
name: TRR 142 - Project Area C
- _id: '174'
name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen
Systemen: Eine theoretische Analyse'
- _id: '266'
name: 'PhoQC: Photonisches Quantencomputing'
publication: Physical Review Research
publication_identifier:
issn:
- 2643-1564
publication_status: published
publisher: American Physical Society (APS)
status: public
title: Multiphoton, multimode state classification for nonlinear optical circuits
type: journal_article
user_id: '16199'
volume: 7
year: '2025'
...
---
_id: '63021'
abstract:
- lang: eng
text: Bell measurements, entailing the projection onto one of the Bell states,
play a key role in quantum information and communication, where the outcome of
a variety of protocols crucially depends on the success probability of such measurements.
Although in the case of qubit systems, Bell measurements can be implemented using
only linear optical components, the same result is no longer true for qudits,
where at least the use of ancillary photons is required. In order to circumvent
this limitation, one possibility is to introduce nonlinear effects. In this work,
we adopt the latter approach and propose a scalable Bell measurement scheme for
high-dimensional states, exploiting multiple squeezer devices applied to a linear
optical circuit for discriminating the different Bell states. Our approach does
not require ancillary photons, is not limited by the dimension of the quantum
states, and is experimentally scalable, thus paving the way toward the realization
of an effective high-dimensional Bell measurement.
article_number: '023038'
author:
- first_name: Luca
full_name: Bianchi, Luca
last_name: Bianchi
- first_name: Carlo
full_name: Marconi, Carlo
last_name: Marconi
- first_name: Jan
full_name: Sperling, Jan
id: '75127'
last_name: Sperling
orcid: 0000-0002-5844-3205
- first_name: Davide
full_name: Bacco, Davide
last_name: Bacco
citation:
ama: Bianchi L, Marconi C, Sperling J, Bacco D. Predetection squeezing as a resource
for high-dimensional Bell-state measurements. Physical Review Research.
2025;7(2). doi:10.1103/physrevresearch.7.023038
apa: Bianchi, L., Marconi, C., Sperling, J., & Bacco, D. (2025). Predetection
squeezing as a resource for high-dimensional Bell-state measurements. Physical
Review Research, 7(2), Article 023038. https://doi.org/10.1103/physrevresearch.7.023038
bibtex: '@article{Bianchi_Marconi_Sperling_Bacco_2025, title={Predetection squeezing
as a resource for high-dimensional Bell-state measurements}, volume={7}, DOI={10.1103/physrevresearch.7.023038},
number={2023038}, journal={Physical Review Research}, publisher={American Physical
Society (APS)}, author={Bianchi, Luca and Marconi, Carlo and Sperling, Jan and
Bacco, Davide}, year={2025} }'
chicago: Bianchi, Luca, Carlo Marconi, Jan Sperling, and Davide Bacco. “Predetection
Squeezing as a Resource for High-Dimensional Bell-State Measurements.” Physical
Review Research 7, no. 2 (2025). https://doi.org/10.1103/physrevresearch.7.023038.
ieee: 'L. Bianchi, C. Marconi, J. Sperling, and D. Bacco, “Predetection squeezing
as a resource for high-dimensional Bell-state measurements,” Physical Review
Research, vol. 7, no. 2, Art. no. 023038, 2025, doi: 10.1103/physrevresearch.7.023038.'
mla: Bianchi, Luca, et al. “Predetection Squeezing as a Resource for High-Dimensional
Bell-State Measurements.” Physical Review Research, vol. 7, no. 2, 023038,
American Physical Society (APS), 2025, doi:10.1103/physrevresearch.7.023038.
short: L. Bianchi, C. Marconi, J. Sperling, D. Bacco, Physical Review Research 7
(2025).
date_created: 2025-12-10T13:34:53Z
date_updated: 2025-12-10T13:36:11Z
department:
- _id: '623'
- _id: '15'
- _id: '170'
- _id: '706'
- _id: '429'
doi: 10.1103/physrevresearch.7.023038
intvolume: ' 7'
issue: '2'
language:
- iso: eng
publication: Physical Review Research
publication_identifier:
issn:
- 2643-1564
publication_status: published
publisher: American Physical Society (APS)
status: public
title: Predetection squeezing as a resource for high-dimensional Bell-state measurements
type: journal_article
user_id: '75127'
volume: 7
year: '2025'
...
---
_id: '62859'
abstract:
- lang: eng
text: Frequency-filtered photon correlations have been proven to be extremely
useful in grasping how the detection process alters photon statistics. Harnessing
the spectral correlations also permits refinement of the emission and unraveling
of previously hidden strong correlations in a plethora of quantum-optical systems
under continuous-wave excitation. In this work, we investigate such correlations
for time-dependent excitation and develop a methodology to compute efficiently
time-integrated correlations, which are at the heart of the photon-counting theory,
and subsequently apply it to analyze the photon emission of pulsed systems. By
combining this formalism with the —which facilitates frequency-resolved correlations—we
demonstrate how spectral filtering enhances single-photon purity and suppresses
multiphoton noise in time-bin-encoded quantum states. Specifically, filtering
the central spectral peak of a dynamically driven two-level system boosts temporal
coherence and improves the fidelity of time-bin entanglement preparation, even
under conditions favoring multiphoton emission. These results establish spectral
filtering as a critical tool for tailoring photon statistics in pulsed quantum
light sources.
article_number: '033296'
author:
- first_name: Santiago
full_name: Bermúdez-Feijóo, Santiago
last_name: Bermúdez-Feijóo
- first_name: Eduardo
full_name: Zubizarreta Casalengua, Eduardo
last_name: Zubizarreta Casalengua
- first_name: Kai
full_name: Müller, Kai
last_name: Müller
- first_name: Klaus
full_name: Jöns, Klaus
id: '85353'
last_name: Jöns
citation:
ama: Bermúdez-Feijóo S, Zubizarreta Casalengua E, Müller K, Jöns K. Spectral correlations
of dynamical resonance fluorescence. Physical Review Research. 2025;7(3).
doi:10.1103/jmy9-bd3l
apa: Bermúdez-Feijóo, S., Zubizarreta Casalengua, E., Müller, K., & Jöns, K.
(2025). Spectral correlations of dynamical resonance fluorescence. Physical
Review Research, 7(3), Article 033296. https://doi.org/10.1103/jmy9-bd3l
bibtex: '@article{Bermúdez-Feijóo_Zubizarreta Casalengua_Müller_Jöns_2025, title={Spectral
correlations of dynamical resonance fluorescence}, volume={7}, DOI={10.1103/jmy9-bd3l},
number={3033296}, journal={Physical Review Research}, publisher={American Physical
Society (APS)}, author={Bermúdez-Feijóo, Santiago and Zubizarreta Casalengua,
Eduardo and Müller, Kai and Jöns, Klaus}, year={2025} }'
chicago: Bermúdez-Feijóo, Santiago, Eduardo Zubizarreta Casalengua, Kai Müller,
and Klaus Jöns. “Spectral Correlations of Dynamical Resonance Fluorescence.” Physical
Review Research 7, no. 3 (2025). https://doi.org/10.1103/jmy9-bd3l.
ieee: 'S. Bermúdez-Feijóo, E. Zubizarreta Casalengua, K. Müller, and K. Jöns, “Spectral
correlations of dynamical resonance fluorescence,” Physical Review Research,
vol. 7, no. 3, Art. no. 033296, 2025, doi: 10.1103/jmy9-bd3l.'
mla: Bermúdez-Feijóo, Santiago, et al. “Spectral Correlations of Dynamical Resonance
Fluorescence.” Physical Review Research, vol. 7, no. 3, 033296, American
Physical Society (APS), 2025, doi:10.1103/jmy9-bd3l.
short: S. Bermúdez-Feijóo, E. Zubizarreta Casalengua, K. Müller, K. Jöns, Physical
Review Research 7 (2025).
date_created: 2025-12-04T12:19:04Z
date_updated: 2025-12-11T12:52:24Z
department:
- _id: '623'
- _id: '15'
- _id: '429'
- _id: '642'
doi: 10.1103/jmy9-bd3l
intvolume: ' 7'
issue: '3'
language:
- iso: eng
publication: Physical Review Research
publication_identifier:
issn:
- 2643-1564
publication_status: published
publisher: American Physical Society (APS)
status: public
title: Spectral correlations of dynamical resonance fluorescence
type: journal_article
user_id: '48188'
volume: 7
year: '2025'
...
---
_id: '63160'
article_number: '245304'
author:
- first_name: Hendrik
full_name: Rose, Hendrik
id: '55958'
last_name: Rose
orcid: 0000-0002-3079-5428
- first_name: Stefan
full_name: Schumacher, Stefan
id: '27271'
last_name: Schumacher
orcid: 0000-0003-4042-4951
- first_name: Torsten
full_name: Meier, Torsten
id: '344'
last_name: Meier
orcid: 0000-0001-8864-2072
citation:
ama: 'Rose H, Schumacher S, Meier T. Microscopic approach to the quantized light-matter
interaction in semiconductor nanostructures: Complex coupled dynamics of excitons,
biexcitons, and photons. Physical Review B. 2025;112(24). doi:10.1103/528f-7smh'
apa: 'Rose, H., Schumacher, S., & Meier, T. (2025). Microscopic approach to
the quantized light-matter interaction in semiconductor nanostructures: Complex
coupled dynamics of excitons, biexcitons, and photons. Physical Review B,
112(24), Article 245304. https://doi.org/10.1103/528f-7smh'
bibtex: '@article{Rose_Schumacher_Meier_2025, title={Microscopic approach to the
quantized light-matter interaction in semiconductor nanostructures: Complex coupled
dynamics of excitons, biexcitons, and photons}, volume={112}, DOI={10.1103/528f-7smh},
number={24245304}, journal={Physical Review B}, publisher={American Physical Society
(APS)}, author={Rose, Hendrik and Schumacher, Stefan and Meier, Torsten}, year={2025}
}'
chicago: 'Rose, Hendrik, Stefan Schumacher, and Torsten Meier. “Microscopic Approach
to the Quantized Light-Matter Interaction in Semiconductor Nanostructures: Complex
Coupled Dynamics of Excitons, Biexcitons, and Photons.” Physical Review B
112, no. 24 (2025). https://doi.org/10.1103/528f-7smh.'
ieee: 'H. Rose, S. Schumacher, and T. Meier, “Microscopic approach to the quantized
light-matter interaction in semiconductor nanostructures: Complex coupled dynamics
of excitons, biexcitons, and photons,” Physical Review B, vol. 112, no.
24, Art. no. 245304, 2025, doi: 10.1103/528f-7smh.'
mla: 'Rose, Hendrik, et al. “Microscopic Approach to the Quantized Light-Matter
Interaction in Semiconductor Nanostructures: Complex Coupled Dynamics of Excitons,
Biexcitons, and Photons.” Physical Review B, vol. 112, no. 24, 245304,
American Physical Society (APS), 2025, doi:10.1103/528f-7smh.'
short: H. Rose, S. Schumacher, T. Meier, Physical Review B 112 (2025).
date_created: 2025-12-16T15:50:42Z
date_updated: 2025-12-16T15:52:55Z
department:
- _id: '15'
- _id: '170'
- _id: '293'
- _id: '297'
- _id: '623'
- _id: '429'
- _id: '230'
- _id: '35'
- _id: '27'
doi: 10.1103/528f-7smh
intvolume: ' 112'
issue: '24'
language:
- iso: eng
project:
- _id: '53'
name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten
zu funktionellen Strukturen'
- _id: '54'
name: TRR 142 - Project Area A
- _id: '59'
name: 'TRR 142; TP A02: Nichtlineare Spektroskopie von Halbleiter-Nanostrukturen
mit Quantenlicht'
- _id: '445'
name: Hochleistungsrechner Noctua in Paderborn
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
- _id: '266'
name: 'PhoQC: Photonisches Quantencomputing'
publication: Physical Review B
publication_identifier:
issn:
- 2469-9950
- 2469-9969
publication_status: published
publisher: American Physical Society (APS)
status: public
title: 'Microscopic approach to the quantized light-matter interaction in semiconductor
nanostructures: Complex coupled dynamics of excitons, biexcitons, and photons'
type: journal_article
user_id: '16199'
volume: 112
year: '2025'
...