@article{60466,
author = {{Brockmeier, Julian and Schapeler, Timon and Lange, Nina Amelie and Höpker, Jan Philipp and Herrmann, Harald and Silberhorn, Christine and Bartley, Tim}},
journal = {{New Journal of Physics}},
title = {{{Harnessing temporal dispersion for integrated pump filtering in spontaneous heralded single-photon generation processes}}},
doi = {{10.1088/1367-2630/ade46c}},
year = {{2025}},
}
@article{48399,
abstract = {{Quantum photonic processing via electro-optic components typically requires electronic links across different operation environments, especially when interfacing cryogenic components such as superconducting single photon detectors with room-temperature control and readout electronics. However, readout and driving electronics can introduce detrimental parasitic effects. Here we show an all-optical control and readout of a superconducting nanowire single photon detector (SNSPD), completely electrically decoupled from room temperature electronics. We provide the operation power for the superconducting detector via a cryogenic photodiode, and readout single photon detection signals via a cryogenic electro-optic modulator in the same cryostat. This method opens the possibility for control and readout of superconducting circuits, and feedforward for photonic quantum computing.}},
author = {{Thiele, Frederik and Hummel, Thomas and McCaughan, Adam N. and Brockmeier, Julian and Protte, Maximilian and Quiring, Victor and Lengeling, Sebastian and Eigner, Christof and Silberhorn, Christine and Bartley, Tim}},
issn = {{1094-4087}},
journal = {{Optics Express}},
keywords = {{Atomic and Molecular Physics, and Optics}},
number = {{20}},
publisher = {{Optica Publishing Group}},
title = {{{All optical operation of a superconducting photonic interface}}},
doi = {{10.1364/oe.492035}},
volume = {{31}},
year = {{2023}},
}
@article{33672,
abstract = {{Abstract
Lithium niobate is a promising platform for integrated quantum optics. In this platform, we aim to efficiently manipulate and detect quantum states by combining superconducting single photon detectors and modulators. The cryogenic operation of a superconducting single photon detector dictates the optimisation of the electro-optic modulators under the same operating conditions. To that end, we characterise a phase modulator, directional coupler, and polarisation converter at both ambient and cryogenic temperatures. The operation voltage
V
π
/
2
of these modulators increases, due to the decrease in the electro-optic effect, by 74% for the phase modulator, 84% for the directional coupler and 35% for the polarisation converter below 8.5
K
. The phase modulator preserves its broadband nature and modulates light in the characterised wavelength range. The unbiased bar state of the directional coupler changed by a wavelength shift of 85
n
m
while cooling the device down to 5
K
. The polarisation converter uses periodic poling to phasematch the two orthogonal polarisations. The phasematched wavelength of the utilised poling changes by 112
n
m
when cooling to 5
K
.}},
author = {{Thiele, Frederik and vom Bruch, Felix and Brockmeier, Julian and Protte, Maximilian and Hummel, Thomas and Ricken, Raimund and Quiring, Viktor and Lengeling, Sebastian and Herrmann, Harald and Eigner, Christof and Silberhorn, Christine and Bartley, Tim}},
issn = {{2515-7647}},
journal = {{Journal of Physics: Photonics}},
keywords = {{Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials}},
number = {{3}},
publisher = {{IOP Publishing}},
title = {{{Cryogenic electro-optic modulation in titanium in-diffused lithium niobate waveguides}}},
doi = {{10.1088/2515-7647/ac6c63}},
volume = {{4}},
year = {{2022}},
}
@article{23826,
abstract = {{Potassium titanyl phosphate (KTP) is a nonlinear optical material with applications in high-power frequency conversion or quasi-phase matching in submicron period domain grids. A prerequisite for these applications is a precise control and understanding of the poling mechanisms to enable the fabrication of high-grade domain grids. In contrast to the widely used material lithium niobate, the domain growth in KTP is less studied, because many standard methods, such as selective etching or polarization microscopy, provides less insight or are not applicable on non-polar surfaces, respectively. In this work, we present results of confocal Raman-spectroscopy of the ferroelectric domain structure in KTP. This analytical method allows for the visualization of domain grids of the non-polar KTP y-face and therefore more insight into the domain-growth and -structure in KTP, which can be used for improved domain fabrication.}},
author = {{Brockmeier, Julian and Mackwitz, Peter Walter Martin and Rüsing, Michael and Eigner, Christof and Padberg, Laura and Santandrea, Matteo and Silberhorn, Christine and Zrenner, Artur and Berth, Gerhard}},
issn = {{2073-4352}},
journal = {{Crystals}},
title = {{{Non-Invasive Visualization of Ferroelectric Domain Structures on the Non-Polar y-Surface of KTiOPO4 via Raman Imaging}}},
doi = {{10.3390/cryst11091086}},
year = {{2021}},
}
@article{25920,
author = {{Padberg, Laura and Santandrea, Matteo and Rüsing, Michael and Brockmeier, Julian and Mackwitz, Peter and Berth, Gerhard and Zrenner, Artur and Eigner, Christof and Silberhorn, Christine}},
issn = {{1094-4087}},
journal = {{Optics Express}},
title = {{{Characterisation of width-dependent diffusion dynamics in rubidium-exchanged KTP waveguides}}},
doi = {{10.1364/oe.397074}},
year = {{2020}},
}
@article{4769,
abstract = {{In recent years, Raman spectroscopy has been used to visualize and analyze ferroelectric domain structures.
The technique makes use of the fact that the intensity or frequency of certain phonons is strongly influenced
by the presence of domain walls. Although the method is used frequently, the underlying mechanism responsible
for the changes in the spectra is not fully understood. This inhibits deeper analysis of domain structures based
on this method. Two different models have been proposed. However, neither model completely explains all
observations. In this work, we have systematically investigated domain walls in different scattering geometries
with Raman spectroscopy in the common ferroelectric materials used in integrated optics, i.e., KTiOPO4,
LiNbO3, and LiTaO3. Based on the two models, we can demonstrate that the observed contrast for domain
walls is in fact based on two different effects. We can identify on the one hand microscopic changes at the
domain wall, e.g., strain and electric fields, and on the other hand a macroscopic change of selection rules at the
domain wall. While the macroscopic relaxation of selection rules can be explained by the directional dispersion
of the phonons in agreement with previous propositions, the microscopic changes can be explained qualitatively
in terms of a simplified atomistic model.}},
author = {{Rüsing, Michael and Neufeld, Sergej and Brockmeier, Julian and Eigner, Christof and Mackwitz, P. and Spychala, K. and Silberhorn, Christine and Schmidt, Wolf Gero and Berth, Gerhard and Zrenner, Artur and Sanna, S.}},
issn = {{2475-9953}},
journal = {{Physical Review Materials}},
number = {{10}},
publisher = {{American Physical Society (APS)}},
title = {{{Imaging of 180∘ ferroelectric domain walls in uniaxial ferroelectrics by confocal Raman spectroscopy: Unraveling the contrast mechanism}}},
doi = {{10.1103/physrevmaterials.2.103801}},
volume = {{2}},
year = {{2018}},
}