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 - TY - JOUR AU - Gil López, Jano AU - Santandrea, Matteo AU - Roland, Ganaël AU - Brecht, Benjamin AU - Eigner, Christof AU - Ricken, Raimund AU - Quiring, Viktor AU - Silberhorn, Christine ID - 22770 JF - New Journal of Physics SN - 1367-2630 TI - Improved non-linear devices for quantum applications ER - TY - JOUR AU - Gil López, Jano AU - Teo, Yong Siah AU - De, Syamsundar AU - Brecht, Benjamin AU - Jeong, Hyunseok AU - Silberhorn, Christine AU - Sánchez-Soto, Luis L. ID - 26410 JF - Optica SN - 2334-2536 TI - Universal compressive tomography in the time-frequency domain ER - TY - JOUR AU - Luo, Kai Hong AU - Santandrea, Matteo AU - Stefszky, Michael AU - Sperling, Jan AU - Massaro, Marcello AU - Ferreri, Alessandro AU - Sharapova, Polina AU - Herrmann, Harald AU - Silberhorn, Christine ID - 26889 JF - Physical Review A SN - 2469-9926 TI - Quantum optical coherence: From linear to nonlinear interferometers ER - TY - JOUR AU - Bagrets, Dmitry AU - Kim, Kun Woo AU - Barkhofen, Sonja AU - De, Syamsundar AU - Sperling, Jan AU - Silberhorn, Christine AU - Altland, Alexander AU - Micklitz, Tobias ID - 26284 JF - Physical Review Research SN - 2643-1564 TI - Probing the topological Anderson transition with quantum walks ER - TY - JOUR AU - Geraldi, Andrea AU - De, Syamsundar AU - Laneve, Alessandro AU - Barkhofen, Sonja AU - Sperling, Jan AU - Mataloni, Paolo AU - Silberhorn, Christine ID - 26287 JF - Physical Review Research SN - 2643-1564 TI - Transient subdiffusion via disordered quantum walks ER - TY - JOUR AU - Tiedau, J. AU - Engelkemeier, M. AU - Brecht, Benjamin AU - Sperling, Jan AU - Silberhorn, Christine ID - 21021 JF - Physical Review Letters SN - 0031-9007 TI - Statistical Benchmarking of Scalable Photonic Quantum Systems VL - 126 ER - TY - JOUR AU - Prasannan, Nidhin AU - De, Syamsundar AU - Barkhofen, Sonja AU - Brecht, Benjamin AU - Silberhorn, Christine AU - Sperling, Jan ID - 26286 JF - Physical Review A SN - 2469-9926 TI - Experimental entanglement characterization of two-rebit states VL - 103 ER - TY - JOUR AB - 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. AU - Brockmeier, Julian AU - Mackwitz, Peter Walter Martin AU - Rüsing, Michael AU - Eigner, Christof AU - Padberg, Laura AU - Santandrea, Matteo AU - Silberhorn, Christine AU - Zrenner, Artur AU - Berth, Gerhard ID - 23826 JF - Crystals SN - 2073-4352 TI - Non-Invasive Visualization of Ferroelectric Domain Structures on the Non-Polar y-Surface of KTiOPO4 via Raman Imaging ER - TY - JOUR AU - Santandrea, Matteo AU - Stefszky, Michael AU - Roeland, Ganaël AU - Silberhorn, Christine ID - 26223 JF - Optics Express SN - 1094-4087 TI - Interferometric method for determining the losses of spatially multi-mode nonlinear waveguides based on second harmonic generation ER - TY - JOUR AU - Stefszky, Michael AU - Santandrea, Matteo AU - vom Bruch, Felix AU - Krapick, S. AU - Eigner, Christof AU - Ricken, R. AU - Quiring, V. AU - Herrmann, Harald AU - Silberhorn, Christine ID - 22771 JF - Optics Express SN - 1094-4087 TI - Waveguide resonator with an integrated phase modulator for second harmonic generation ER - TY - JOUR AB - We present a time-over-threshold readout technique to count the number of activated pixels from an array of superconducting nanowire single photon detectors (SNSPDs). This technique places no additional heatload on the cryostat, and retains the intrinsic count rate of the time-tagger. We demonstrate proof-of-principle operation with respect to a four-pixel device. Furthermore, we show that, given some permissible error threshold, the number of pixels that can be reliably read out scales linearly with the intrinsic signal-to-noise ratio of the individual pixel response. AU - Tiedau, Johannes AU - Schapeler, Timon AU - Anant, Vikas AU - Fedder, Helmut AU - Silberhorn, Christine AU - Bartley, Tim ID - 37933 IS - 4 JF - Optics Express KW - Atomic and Molecular Physics KW - and Optics SN - 1094-4087 TI - Single-channel electronic readout of a multipixel superconducting nanowire single photon detector VL - 28 ER - TY - JOUR AB - The characterisation of loss in optical waveguides is essential in understanding the performance of these devices and their limitations. Whilst interferometric-based methods generally provide the best results for low-loss waveguides, they are almost exclusively used to provide characterization in cases where the waveguide is spatially single-mode. Here, we introduce a Fabry-Pérot-based scheme to estimate the losses of a nonlinear (birefringent or quasi-phase matched) waveguide at a wavelength where it is multi-mode. The method involves measuring the generated second harmonic power as the pump wavelength is scanned over the phase matching region. Furthermore, it is shown that this method allows one to infer the losses of different second harmonic spatial modes by scanning the pump field over the separated phase matching spectra. By fitting the measured phase matching spectra from different titanium indiffused lithium niobate waveguides to the model presented in this paper, it is shown that one can estimate the second harmonic losses of a single spatial-mode, at wavelengths where the waveguides are spatially multi-mode. AU - Santandrea, Matteo AU - Stefszky, Michael AU - Roeland, Ganaël AU - Silberhorn, Christine ID - 38051 IS - 4 JF - Optics Express KW - Atomic and Molecular Physics KW - and Optics SN - 1094-4087 TI - Interferometric method for determining the losses of spatially multi-mode nonlinear waveguides based on second harmonic generation. VL - 28 ER - TY - JOUR AU - Mukamel, Shaul AU - Freyberger, Matthias AU - Schleich, Wolfgang AU - Bellini, Marco AU - Zavatta, Alessandro AU - Leuchs, Gerd AU - Silberhorn, Christine AU - Boyd, Robert W AU - Sánchez-Soto, Luis Lorenzo AU - Stefanov, André AU - Barbieri, Marco AU - Paterova, Anna AU - Krivitsky, Leonid AU - Shwartz, Sharon AU - Tamasaku, Kenji AU - Dorfman, Konstantin AU - Schlawin, Frank AU - Sandoghdar, Vahid AU - Raymer, Michael AU - Marcus, Andrew AU - Varnavski, Oleg AU - Goodson, Theodore AU - Zhou, Zhi-Yuan AU - Shi, Bao-Sen AU - Asban, Shahaf AU - Scully, Marlan AU - Agarwal, Girish AU - Peng, Tao AU - Sokolov, Alexei V AU - Zhang, Zhe-Dong AU - Zubairy, M Suhail AU - Vartanyants, Ivan A AU - del Valle, Elena AU - Laussy, Fabrice ID - 37934 IS - 7 JF - Journal of Physics B: Atomic, Molecular and Optical Physics KW - Condensed Matter Physics KW - Atomic and Molecular Physics KW - and Optics SN - 0953-4075 TI - Roadmap on quantum light spectroscopy VL - 53 ER - TY - JOUR AU - Meyer-Scott, Evan AU - Silberhorn, Christine AU - Migdall, Alan ID - 37935 IS - 4 JF - Review of Scientific Instruments KW - Instrumentation SN - 0034-6748 TI - Single-photon sources: Approaching the ideal through multiplexing VL - 91 ER - TY - JOUR AB - Hybrid quantum information processing combines the advantages of discrete and continues variable protocols by realizing protocols consisting of photon counting and homodyne measurements. However, the mode structure of pulsed sources and the properties of the detection schemes often require the use of optical filters in order to combine both detection methods in a common experiment. This limits the efficiency and the overall achievable squeezing of the experiment. In our work, we use photon subtraction to implement the distillation of pulsed squeezed states originating from a genuinely spatially and temporally single-mode parametric down-conversion source in non-linear waveguides. Due to the distillation, we witness an improvement of 0.17 dB from an initial squeezing value of −1.648 ± 0.002 dB, while achieving a purity of 0.58, and confirm the non-Gaussianity of the distilled state via the higher-order cumulants. With this, we demonstrate the source’s suitability for scalable hybrid quantum network applications with pulsed quantum light. AU - Dirmeier, Thomas AU - Tiedau, Johannes AU - Khan, Imran AU - Ansari, Vahid AU - Müller, Christian R. AU - Silberhorn, Christine AU - Marquardt, Christoph AU - Leuchs, Gerd ID - 37932 IS - 21 JF - Optics Express KW - Atomic and Molecular Physics KW - and Optics SN - 1094-4087 TI - Distillation of squeezing using an engineered pulsed parametric down-conversion source VL - 28 ER - TY - JOUR AU - Eigner, Christof AU - Padberg, Laura AU - Santandrea, Matteo AU - Herrmann, Harald AU - Brecht, Benjamin AU - Silberhorn, Christine ID - 21025 IS - 22 JF - Optics Express SN - 1094-4087 TI - Spatially single mode photon pair source at 800 nm in periodically poled Rubidium exchanged KTP waveguides VL - 28 ER - TY - JOUR AB - Abstract The phenomenon of entanglement is the basis of quantum information and quantum communication processes. Entangled systems with a large number of photons are of great interest at present because they provide a platform for streaming technologies based on photonics. In this paper we present a device which operates with four-photons and based on the Hong–Ou–Mandel interference. The presented device allows to maximize the degree of spatial entanglement and generate the highly entangled four-dimensional Bell states. Furthermore, the use of the interferometer in different regimes leads to fast interference fringes in the coincidence probability with period of oscillations twice smaller than the pump wavelength. We have a good agreement between theoretical simulations and experimental results. AU - Ferreri, A AU - Ansari, V AU - Brecht, Benjamin AU - Silberhorn, Christine AU - Sharapova, Polina R. ID - 40381 IS - 4 JF - Quantum Science and Technology KW - Electrical and Electronic Engineering KW - Physics and Astronomy (miscellaneous) KW - Materials Science (miscellaneous) KW - Atomic and Molecular Physics KW - and Optics SN - 2058-9565 TI - Spatial entanglement and state engineering via four-photon Hong–Ou–Mandel interference VL - 5 ER - TY - JOUR AU - Sperling, Jan AU - Phillips, D. S. AU - Bulmer, J. F. F AU - Thekkadath, G. S. AU - Eckstein, A. AU - Wolterink, T. A. W. AU - Lugani, J. AU - Nam, S. W. AU - Lita, A. AU - Gerrits, T. AU - Vogel, W. AU - Agarwal, G. S. AU - Silberhorn, Christine AU - Walmsley, I. A. ID - 26294 JF - Physical Review Letters SN - 0031-9007 TI - Detector-Agnostic Phase-Space Distributions ER - TY - JOUR AU - Engelkemeier, M. AU - Lorz, L. AU - De, Syamsundar AU - Brecht, Benjamin AU - Dhand, I. AU - Plenio, M. B. AU - Silberhorn, Christine AU - Sperling, Jan ID - 21023 JF - Physical Review A SN - 2469-9926 TI - Quantum photonics with active feedback loops VL - 102 ER - TY - JOUR AU - Nitsche, Thomas AU - De, Syamsundar AU - Barkhofen, Sonja AU - Meyer-Scott, Evan AU - Tiedau, Johannes AU - Sperling, Jan AU - Gábris, Aurél AU - Jex, Igor AU - Silberhorn, Christine ID - 26289 JF - Physical Review Letters SN - 0031-9007 TI - Local Versus Global Two-Photon Interference in Quantum Networks ER - TY - JOUR AB - Polarons in dielectric crystals play a crucial role for applications in integrated electronics and optoelectronics. In this work, we use density-functional theory and Green's function methods to explore the microscopic structure and spectroscopic signatures of electron polarons in lithium niobate (LiNbO3). Total-energy calculations and the comparison of calculated electron paramagnetic resonance data with available measurements reveal the formation of bound polarons at Nb_Li antisite defects with a quasi-Jahn-Teller distorted, tilted configuration. The defect-formation energies further indicate that (bi)polarons may form not only at Nb_Li antisites but also at structures where the antisite Nb atom moves into a neighboring empty oxygen octahedron. Based on these structure models, and on the calculated charge-transition levels and potential-energy barriers, we propose two mechanisms for the optical and thermal splitting of bipolarons, which provide a natural explanation for the reported two-path recombination of bipolarons. Optical-response calculations based on the Bethe-Salpeter equation, in combination with available experimental data and new measurements of the optical absorption spectrum, further corroborate the geometries proposed here for free and defect-bound (bi)polarons. AU - Schmidt, Falko AU - Kozub, Agnieszka L. AU - Biktagirov, Timur AU - Eigner, Christof AU - Silberhorn, Christine AU - Schindlmayr, Arno AU - Schmidt, Wolf Gero AU - Gerstmann, Uwe ID - 19190 IS - 4 JF - Physical Review Research TI - Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations VL - 2 ER - TY - JOUR AU - Bocchini, Adriana AU - Eigner, Christof AU - Silberhorn, Christine AU - Schmidt, Wolf Gero AU - Gerstmann, Uwe ID - 20682 JF - Phys. Rev. Materials TI - Understanding gray track formation in KTP: Ti^3+ centers studied from first principles VL - 4 ER - TY - JOUR AU - Padberg, Laura AU - Santandrea, Matteo AU - Rüsing, Michael AU - Brockmeier, Julian AU - Mackwitz, Peter AU - Berth, Gerhard AU - Zrenner, Artur AU - Eigner, Christof AU - Silberhorn, Christine ID - 25920 JF - Optics Express SN - 1094-4087 TI - Characterisation of width-dependent diffusion dynamics in rubidium-exchanged KTP waveguides ER - TY - JOUR AU - Massaro, Marcello AU - Meyer-Scott, Evan AU - Montaut, Nicola AU - Herrmann, Harald AU - Silberhorn, Christine ID - 25038 JF - New Journal of Physics SN - 1367-2630 TI - Improving SPDC single-photon sources via extended heralding and feed-forward control ER - TY - JOUR AU - Santandrea, Matteo AU - Stefszky, Michael AU - Roeland, Ganaël AU - Silberhorn, Christine ID - 26224 JF - New Journal of Physics SN - 1367-2630 TI - Characterisation of fabrication inhomogeneities in Ti:LiNbO3 waveguides ER - TY - JOUR AU - Santandrea, Matteo AU - Stefszky, Michael AU - Ansari, Vahid AU - Silberhorn, Christine ID - 26226 JF - New Journal of Physics SN - 1367-2630 TI - Fabrication limits of waveguides in nonlinear crystals and their impact on quantum optics applications ER - TY - JOUR AU - Luo, Kai-Hong AU - Ansari, Vahid AU - Massaro, Marcello AU - Santandrea, Matteo AU - Eigner, Christof AU - Ricken, Raimund AU - Herrmann, Harald AU - Silberhorn, Christine ID - 26237 JF - Optics Express SN - 1094-4087 TI - Counter-propagating photon pair generation in a nonlinear waveguide ER - TY - CONF AU - Meyer-Scott, Evan AU - Prasannan, Nidhin AU - Montaut, Nicola AU - Tiedau, Johannes AU - Eigner, Christof AU - Harder, Georg AU - Sansoni, Linda AU - Nitsche, Thomas AU - Herrmann, Harald AU - Ricken, Raimund AU - Quiring, Viktor AU - Bartley, Tim AU - Barkhofen, Sonja AU - Silberhorn, Christine ED - Hasan, Zameer U. ED - Hemmer, Philip R. ED - Migdall, Alan L. ID - 9635 SN - 9781510625082 T2 - Advances in Photonics of Quantum Computing, Memory, and Communication XII TI - Engineering integrated photon pair sources and multiplexed detectors (Conference Presentation) ER - TY - GEN AU - Padberg, Laura AU - Eigner, Christof AU - Santandrea, Matteo AU - Silberhorn, Christine ID - 38138 TI - Herstellung von Wellenleitern aus Materialien der KTP-Familie ER - TY - JOUR AU - Xie, Zhenda AU - Luo, Kai Hong AU - Chang, Kai Chi AU - Panoiu, Nicolae C. AU - Herrmann, Harald AU - Silberhorn, Christine AU - Wong, Chee Wei ID - 38047 IS - 22 JF - Applied Optics KW - Atomic and Molecular Physics KW - and Optics KW - Engineering (miscellaneous) KW - Electrical and Electronic Engineering SN - 1559-128X TI - Efficient C-band single-photon upconversion with chip-scale Ti-indiffused pp-LiNbO3 waveguides VL - 58 ER -