TY - JOUR
AB - Ferroelectric domain wall (DW) conductivity (DWC) can be attributed to two separate mechanisms: (a) the injection/ejection of charge carriers across the Schottky barrier formed at the (metal-)electrode-DW junction and (b) the transport of those charge carriers along the DW. Current-voltage (I-U) characteristics, recorded at variable temperatures from LiNbO3 (LNO) DWs, are clearly able to differentiate between these two contributions. Practically, they allow us to directly quantify the physical parameters relevant to the two mechanisms (a) and (b) mentioned above. These are, for example, the resistance of the DW, the saturation current, the ideality factor, and the Schottky barrier height of the electrode-DW junction. Furthermore, the activation energies needed to initiate the thermally activated electronic transport along the DWs can be extracted. In addition, we show that electronic transport along LNO DWs can be elegantly viewed and interpreted in an adapted semiconductor picture based on a double-diode, double-resistor equivalent-circuit model, the R2D2 model. Finally, our R2D2 model was checked for its universality by successfully fitting the I-U curves of not only z-cut LNO bulk DWs, but equally of z-cut thin-film LNO DWs, and of x-cut thin-film DWs as reported in literature.
AU - Zahn, Manuel
AU - Beyreuther, Elke
AU - Kiseleva, Iuliia
AU - Lotfy, Ahmed Samir
AU - McCluskey, Conor J.
AU - Maguire, Jesi R.
AU - Suna, Ahmet
AU - Rüsing, Michael
AU - Gregg, J. Marty
AU - Eng, Lukas M.
ID - 51156
IS - 2
JF - Physical Review Applied
KW - General Physics and Astronomy
SN - 2331-7019
TI - Equivalent-circuit model that quantitatively describes domain-wall conductivity in ferroelectric lithium
VL - 21
ER -
TY - JOUR
AU - Babai-Hemati, Jonas
AU - vom Bruch, Felix
AU - Herrmann, Harald
AU - Silberhorn, Christine
ID - 51339
JF - Optics Express
KW - Atomic and Molecular Physics
KW - and Optics
SN - 1094-4087
TI - Tailored second harmonic generation inTi-diffused PPLN waveguides usingmicro-heaters
ER -
TY - JOUR
AB - In real photonic quantum systems losses are an unavoidable factor limiting the scalability to many modes and particles, restraining their application in fields as quantum information and communication. For this reason, a considerable amount of engineering effort has been taken in order to improve the quality of particle sources and system components. At the same time, data analysis and collection methods based on post-selection have been used to mitigate the effect of particle losses. This has allowed for investigating experimentally multi-particle evolutions where the observer lacks knowledge about the system's intermediate propagation states. Nonetheless, the fundamental question how losses affect the behaviour of the surviving subset of a multi-particle system has not been investigated so far. For this reason, here we study the impact of particle losses in a quantum walk of two photons reconstructing the output probability distributions for one photon conditioned on the loss of the other in a known mode and temporal step of our evolution network. We present the underlying theoretical scheme that we have devised in order to model controlled particle losses, we describe an experimental platform capable of implementing our theory in a time multiplexing encoding. In the end we show how localized particle losses change the output distributions without altering their asymptotic spreading properties. Finally we devise a quantum civilization problem, a two walker generalisation of single particle recurrence processes.
AU - Pegoraro, Federico
AU - Held, Philip
AU - Barkhofen, Sonja
AU - Brecht, Benjamin
AU - Silberhorn, Christine
ID - 42648
IS - 3
JF - Physica Scripta
SN - 0031-8949
TI - Dynamic conditioning of two particle discrete-time quantum walks
VL - 98
ER -
TY - JOUR
AU - Serino, Laura
AU - Gil López, Jano
AU - Stefszky, Michael
AU - Ricken, Raimund
AU - Eigner, Christof
AU - Brecht, Benjamin
AU - Silberhorn, Christine
ID - 44081
IS - 2
JF - PRX Quantum
KW - General Physics and Astronomy
KW - Mathematical Physics
KW - Applied Mathematics
KW - Electronic
KW - Optical and Magnetic Materials
KW - Electrical and Electronic Engineering
KW - General Computer Science
SN - 2691-3399
TI - Realization of a Multi-Output Quantum Pulse Gate for Decoding High-Dimensional Temporal Modes of Single-Photon States
VL - 4
ER -
TY - JOUR
AU - Kruse, Stephan
AU - Serino, Laura
AU - Folge, Patrick Fabian
AU - Echeverria Oviedo, Dana
AU - Bhattacharjee, Abhinandan
AU - Stefszky, Michael
AU - Scheytt, J. Christoph
AU - Brecht, Benjamin
AU - Silberhorn, Christine
ID - 45485
IS - 14
JF - IEEE Photonics Technology Letters
KW - Electrical and Electronic Engineering
KW - Atomic and Molecular Physics
KW - and Optics
KW - Electronic
KW - Optical and Magnetic Materials
SN - 1041-1135
TI - A Pulsed Lidar System With Ultimate Quantum Range Accuracy
VL - 35
ER -
TY - JOUR
AB - Interference between single photons is key for many quantum optics experiments and applications in quantum technologies, such as quantum communication or computation. It is advantageous to operate the systems at telecommunication wavelengths and to integrate the setups for these applications in order to improve stability, compactness and scalability. A new promising material platform for integrated quantum optics is lithium niobate on insulator (LNOI). Here, we realise Hong-Ou-Mandel (HOM) interference between telecom photons from an engineered parametric down-conversion source in an LNOI directional coupler. The coupler has been designed and fabricated in house and provides close to perfect balanced beam splitting. We obtain a raw HOM visibility of (93.5 ± 0.7) %, limited mainly by the source performance and in good agreement with off-chip measurements. This lays the foundation for more sophisticated quantum experiments in LNOI.
AU - Babel, Silia
AU - Bollmers, Laura
AU - Massaro, Marcello
AU - Luo, Kai Hong
AU - Stefszky, Michael
AU - Pegoraro, Federico
AU - Held, Philip
AU - Herrmann, Harald
AU - Eigner, Christof
AU - Brecht, Benjamin
AU - Padberg, Laura
AU - Silberhorn, Christine
ID - 45850
IS - 14
JF - Optics Express
KW - Atomic and Molecular Physics
KW - and Optics
SN - 1094-4087
TI - Demonstration of Hong-Ou-Mandel interference in an LNOI directional coupler
VL - 31
ER -
TY - JOUR
AB - This work reports a fully guided setup for single-mode squeezing on integrated titanium-indiffused periodically poled nonlinear resonators. A continuous-wave laser beam is delivered and the squeezed field is collected by single-mode fibers; up to −3.17(9) dB of useful squeezing is available in fibers. To showcase the usefulness of such a fiber-coupled device, we applied the generated squeezed light in a fiber-based phase sensing experiment, showing a quantum enhancement in the signal-to-noise ratio of 0.35 dB. Moreover, our investigation of the effect of photorefraction on the cavity resonance condition suggests that it causes system instabilities at high powers.
AU - Domeneguetti, Renato
AU - Stefszky, Michael
AU - Herrmann, Harald
AU - Silberhorn, Christine
AU - Andersen, Ulrik L.
AU - Neergaard-Nielsen, Jonas S.
AU - Gehring, Tobias
ID - 46138
IS - 11
JF - Optics Letters
KW - Atomic and Molecular Physics
KW - and Optics
SN - 0146-9592
TI - Fully guided and phase locked Ti:PPLN waveguide squeezing for applications in quantum sensing
VL - 48
ER -
TY - JOUR
AB - We report a titanium indiffused waveguide resonator featuring an integrated electro-optic modulator for cavity length stabilisation that produces close to 5 dB of squeezed light at 1550 nm (2.4 dB directly measured). The resonator is locked on resonance for tens of minutes with 70 mW of SH light incident on the cavity, demonstrating that photorefraction can be mitigated. Squeezed light production concurrent with cavity length stabilisation utilising the integrated EOM is demonstrated. The device demonstrates the suitability of this platform for squeezed light generation in network applications, where stabilisation to the reference field is typically necessary.
AU - Stefszky, M.
AU - vom Bruch, F.
AU - Santandrea, M.
AU - Ricken, R.
AU - Quiring, V.
AU - Eigner, C.
AU - Herrmann, H
AU - Silberhorn, C
ID - 48349
IS - 21
JF - Optics Express
KW - Atomic and Molecular Physics
KW - and Optics
SN - 1094-4087
TI - Lithium niobate waveguide squeezer with integrated cavity length stabilisation for network applications
VL - 31
ER -
TY - JOUR
AU - Meyer-Scott, Evan
AU - Prasannan, Nidhin
AU - Dhand, Ish
AU - Eigner, Christof
AU - Quiring, Viktor
AU - Barkhofen, Sonja
AU - Brecht, Benjamin
AU - Plenio, Martin B.
AU - Silberhorn, Christine
ID - 40273
IS - 15
JF - Physical Review Letters
KW - General Physics and Astronomy
SN - 0031-9007
TI - Scalable Generation of Multiphoton Entangled States by Active Feed-Forward and Multiplexing
VL - 129
ER -
TY - CONF
AB - We demonstrate theoretically and experimentally complex correlations in the photon numbers of two-mode quantum states using measurement-induced nonlinearity. For this, we combine the interference of coherent states and single photons with photon sub-traction.
AU - Meier, Torsten
AU - Hoepker, Jan Philipp
AU - Protte, Maximilian
AU - Eigner, Christof
AU - Silberhorn, Christine
AU - Sharapova, Polina R.
AU - Sperling, Jan
AU - Bartley, Tim
ID - 43744
SN - 978-1-957171-05-0
T2 - Conference on Lasers and Electro-Optics: Applications and Technology
TI - Two-Mode Photon-Number Correlations Created by Measurement-Induced Nonlinearity
ER -
TY - JOUR
AB - We study the DC conductivity in potassium titanyl phosphate (KTiOPO4, KTP) and its isomorphs KTiOAsO4 (KTA) and Rb1%K99%TiOPO4 (RKTP) and introduce a method by which to reduce the overall ionic conductivity in KTP by a potassium nitrate treatment. Furthermore, we create so-called gray tracking in KTP and investigate the ionic conductivity in theses areas. A local unintended reduction of the ionic conductivity is observed in the gray-tracked regions, which also induce additional optical absorption in the material. We show that a thermal treatment in an oxygen-rich atmosphere removes the gray tracking and brings the ionic conductivity as well as the optical transmission back to the original level. These studies can help to choose the best material and treatment for specific applications.
AU - Padberg, Laura
AU - Quiring, Viktor
AU - Bocchini, Adriana
AU - Santandrea, Matteo
AU - Gerstmann, Uwe
AU - Schmidt, Wolf Gero
AU - Silberhorn, Christine
AU - Eigner, Christof
ID - 33484
JF - Crystals
SN - 2073-4352
TI - DC Ionic Conductivity in KTP and Its Isomorphs: Properties, Methods for Suppression, and Its Connection to Gray Tracking
VL - 12
ER -
TY - JOUR
AU - Prasannan, Nidhin
AU - Sperling, Jan
AU - Brecht, Benjamin
AU - Silberhorn, Christine
ID - 34884
IS - 26
JF - Physical Review Letters
KW - General Physics and Astronomy
SN - 0031-9007
TI - Direct Measurement of Higher-Order Nonlinear Polarization Squeezing
VL - 129
ER -
TY - JOUR
AB - Quantum walks function as essential means to implement quantum simulators, allowing one to study complex and often directly inaccessible quantum processes in controllable systems. In this contribution, the notion of a driven Gaussian quantum walk is introduced. In contrast to typically considered quantum walks in optical settings, we describe the operation of the walk in terms of a nonlinear map rather than a unitary operation, e.g., by replacing a beam-splitter-type coin with a two-mode squeezer, being a process that is controlled and driven by a pump field. This opens previously unattainable possibilities for quantum walks that include nonlinear elements as core components of their operation, vastly extending their range of applications. A full framework for driven Gaussian quantum walks is developed, including methods to dynamically characterize nonlinear, quantum, and quantum-nonlinear effects. Moreover, driven Gaussian quantum walks are compared with their classically interfering and linear counterparts, which are based on classical coherence of light rather than quantum superpositions. In particular, the generation and boost of highly multimode entanglement, squeezing, and other quantum effects are studied over the duration of the nonlinear walk. Importantly, we prove the quantumness of the evolution itself, regardless of the input state. A scheme for an experimental realization is proposed. Furthermore, nonlinear properties of driven Gaussian quantum walks are explored, such as amplification that leads to an ever increasing number of correlated quantum particles, constituting a source of new walkers during the walk. Therefore, a concept for quantum walks is proposed that leads to—and even produces—directly accessible quantum phenomena, and that renders the quantum simulation of nonlinear processes possible.
AU - Held, Philip
AU - Engelkemeier, Melanie
AU - De, Syamsundar
AU - Barkhofen, Sonja
AU - Sperling, Jan
AU - Silberhorn, Christine
ID - 30921
IS - 4
JF - Physical Review A
SN - 2469-9926
TI - Driven Gaussian quantum walks
VL - 105
ER -
TY - JOUR
AU - Santandrea, Matteo
AU - Stefszky, Michael
AU - Silberhorn, Christine
ID - 26218
JF - Journal of Optics
SN - 2040-8978
TI - General analytic theory of classical collinear three-wave mixing in a monolithic cavity
ER -
TY - JOUR
AU - De, Syamsundar
AU - Gil López, Jano
AU - Brecht, Benjamin
AU - Silberhorn, Christine
AU - Sánchez-Soto, Luis L.
AU - Hradil, Zdeněk
AU - Řeháček, Jaroslav
ID - 29524
IS - 3
JF - Physical Review Research
KW - General Engineering
SN - 2643-1564
TI - Effects of coherence on temporal resolution
VL - 3
ER -
TY - JOUR
AU - Ansari, Vahid
AU - Brecht, Benjamin
AU - Gil-Lopez, Jano
AU - Donohue, John M.
AU - Řeháček, Jaroslav
AU - Hradil, Zdeněk
AU - Sánchez-Soto, Luis L.
AU - Silberhorn, Christine
ID - 21020
JF - PRX Quantum
SN - 2691-3399
TI - Achieving the Ultimate Quantum Timing Resolution
VL - 2
ER -
TY - JOUR
AU - Roman-Rodriguez, V
AU - Brecht, Benjamin
AU - Srinivasan, K
AU - Silberhorn, Christine
AU - Treps, N
AU - Diamanti, E
AU - Parigi, V
ID - 22259
JF - New Journal of Physics
SN - 1367-2630
TI - Continuous variable multimode quantum states via symmetric group velocity matching
VL - 23
ER -
TY - GEN
AU - Padberg, Laura
AU - Eigner, Christof
AU - Santandrea, Matteo
AU - Silberhorn, Christine
ID - 38135
TI - Production of waveguides made of materials from the KTP family
ER -
TY - CONF
AB - We present a frequency multimode integrated SU (1,1) interferometer with a polarization converter and strong signal-idler photon correlations. Phase sensitivity below the shot noise limit is demonstrated, various filtering and seeding strategies are discussed.
AU - Ferreri, A.
AU - Santandrea, Matteo
AU - Stefszky, Michael
AU - Luo, Kai Hong
AU - Herrmann, Harald
AU - Silberhorn, Christine
AU - Sharapova, Polina
ID - 40374
T2 - Conference on Lasers and Electro-Optics
TI - Multimode integrated SU(1,1) interferometer
ER -
TY - JOUR
AU - Pelucchi, Emanuele
AU - Fagas, Giorgos
AU - Aharonovich, Igor
AU - Englund, Dirk
AU - Figueroa, Eden
AU - Gong, Qihuang
AU - Hannes, Hübel
AU - Liu, Jin
AU - Lu, Chao-Yang
AU - Matsuda, Nobuyuki
AU - Pan, Jian-Wei
AU - Schreck, Florian
AU - Sciarrino, Fabio
AU - Silberhorn, Christine
AU - Wang, Jianwei
AU - Jöns, Klaus
ID - 37936
IS - 3
JF - Nature Reviews Physics
KW - General Physics and Astronomy
SN - 2522-5820
TI - The potential and global outlook of integrated photonics for quantum technologies
VL - 4
ER -