Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1404.6914 · Physical Review A

Crossed-crystal scheme for femtosecond-pulsed entangled photon generation in periodically poled potassium titanyl phosphate

Thomas Scheidl, Felix Tiefenbacher, Robert Prevedel, Fabian Steinlechner, Rupert Ursin, Anton Zeilinger

Published Apr 23, 2014• 12 citations
arXivHTMLPDF

Abstract

We demonstrate a scheme for femtosecond pulsed spontaneous parametric down-conversion in periodically poled potassium titanyl phosphate crystals. Our scheme is based on a crossed crystal configuration with collinear quasi-phase-matching. The nondegenerate photon pairs are split in a fiber-based wavelength division multiplexer. The source is easier to align than common pulsed sources based on bulk beta barium borate crystals and exhibits high-quality polarization entanglement as well as nonclassical interference capabilities. Hence, we expect this source to be a well-suited candidate for multiphoton state generation, e.g., for linear optical quantum computation and quantum communication networks.

DOI
10.1103/physreva.89.042324

Related papers

A high-brightness source of polarization-entangled photons optimized for applications in free space

Fabian Steinlechner, Pavel Trojek, Marc Jofre +9 more

We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.

arXiv:1204.5330•Optics Express•Apr 12, 2012•108 citations

A high-brightness source of polarization-entangled photons optimized for applications in free space

Steinlechner, F., Trojek, P., Jofre, M. +9 more

We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.

•Apr 23, 2012•56 citations

Extended phase matching properties of periodically poled potassium titanyl phosphate isomorphs

Tae-Hyung Kim, Kwang Jo Lee

We theoretically investigate the properties of extended phase-matching (EPM) for spontaneous parametric down-conversion (SPDC) in four kinds of potassium titanyl phosphate isomorphs ( i.e. , KTiOPO 4 , KTiOAsO 4 , RbTiOPO 4 , and RbTiOAsO 4 crystals). The technique is based on Type II 2nd-order nonlinear optic interaction in periodically poled ferroelectric domain structures, where a single photon with a frequency of 2 ω generates a pair of photons with frequencies of ω that are orthogonally polarized with respect to each other. Under EPM, both quasi-phase matching (QPM) and group velocity (GV) matching between interacting waves are efficiently satisfied for the generation of a pair of polarization-entangled bi-photon states with frequencies of ω . Our simulation results show that the generated photon pairs have broad spectral bandwidths of over 69 - 95 nm in tele-communication bands, which are much broader than those of the typical non-EPM case ( e.g. , ~ sub-nm bandwidth when only the QPM, not the GV matching, is achieved). We will describe the EPM properties of the four kinds of KTP isomorphs in terms of interaction type, GV matching wavelength, domain poling period, and spectral bandwidth. We highlight that the KTP isomorphs have nice potential as suitable components for constituting new quantum information processing systems.

Journal of the Korean Physical Society•Sep 1, 2015•4 citations

Bright Source of Spectrally Uncorrelated Polarization-Entangled Photons with Nearly Single-Mode Emission

Philip G. Evans, Ryan S. Bennink, Warren P. Grice +2 more

We present results of a bright polarization-entangled photon source operating at 1552 nm via type-II collinear degenerate spontaneous parametric down-conversion in a periodically poled potassium titanyl phosphate crystal. We report a conservative inferred pair generation rate of 123,000 pairs/s/mW into collection modes. Minimization of spectral and spatial entanglement was achieved by group velocity matching the pump, signal, and idler modes and through properly focusing the pump beam. By utilizing a pair of calcite beam displacers, we are able to overlap photons from adjacent down-conversion processes to obtain polarization-entanglement visibility of 94.7+/-1.1% with accidentals subtracted.

arXiv:1009.1609•Physical Review Letters•Dec 13, 2010•132 citations

Highly efficient generation of pulsed photon pairs with bulk periodically poled potassium titanyl phosphate

Bao‐Sen Shi, Akihisa Tomita

We demonstrate efficient generation of collinearly propagating, degenerate pulsed photon pairs based on a bulk periodically poled potassium titanyl phosphate pumped by an ultrashort-pulse laser. Using a single-mode fiber as a spatial mode filter, we detect approximately 3200 coincidence counts per second per milliwatt pump power in a Hanbury–Brown–Twiss-type experiment. The estimated photon-pair production rate is approximately 1.05 MHz/mW pump power. This is very promising for the realization of sources for quantum communication and metrology.

arXiv:quant-ph/0310187•Journal of the Optical Society of America B•Dec 1, 2004•21 citations

Polarization-entangled photon-pair source obtained via type-II non-collinear SPDC process with PPKTP crystal

Sang Min Lee, Heonoh Kim, Myoungsik Cha +1 more

We demonstrate a polarization-entangled photon-pair source obtained via a type-II non-collinear quasi-phase-matched spontaneous parametric down-conversion process with a 10-mm periodically poled KTiOPO4 crystal, which is as stable and wavelength-tunable as the well-known Sagnac configuration scheme. A brightness of 4.2 kHz/mW is detected and a concurrence of 0.975 is estimated using quantum state tomography. Without loss of entanglement and brightness, the photon-pair wavelengths are tunable through control of the crystal temperature. This improvement is achieved using the non-collinear configuration and a stable interferometric distinguishability compensator.

arXiv:1512.07698•Optics Express•Feb 4, 2016•55 citations
We demonstrate a scheme for femtosecond pulsed spontaneous parametric down-conversion in periodically poled potassium titanyl phosphate crystals. Our scheme is based on a crossed crystal configuration with collinear quasi-phase-matching. The nondegenerate photon pairs are split in a fiber-based wavelength division multiplexer. The source is easier to align than common pulsed sources based on bulk beta barium borate crystals and exhibits high-quality polarization entanglement as well as nonclassical interference capabilities. Hence, we expect this source to be a well-suited candidate for multiphoton state generation, e.g., for linear optical quantum computation and quantum communication networks.
We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.
We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.
We theoretically investigate the properties of extended phase-matching (EPM) for spontaneous parametric down-conversion (SPDC) in four kinds of potassium titanyl phosphate isomorphs ( i.e. , KTiOPO 4 , KTiOAsO 4 , RbTiOPO 4 , and RbTiOAsO 4 crystals). The technique is based on Type II 2nd-order nonlinear optic interaction in periodically poled ferroelectric domain structures, where a single photon with a frequency of 2 ω generates a pair of photons with frequencies of ω that are orthogonally polarized with respect to each other. Under EPM, both quasi-phase matching (QPM) and group velocity (GV) matching between interacting waves are efficiently satisfied for the generation of a pair of polarization-entangled bi-photon states with frequencies of ω . Our simulation results show that the generated photon pairs have broad spectral bandwidths of over 69 - 95 nm in tele-communication bands, which are much broader than those of the typical non-EPM case ( e.g. , ~ sub-nm bandwidth when only the QPM, not the GV matching, is achieved). We will describe the EPM properties of the four kinds of KTP isomorphs in terms of interaction type, GV matching wavelength, domain poling period, and spectral bandwidth. We highlight that the KTP isomorphs have nice potential as suitable components for constituting new quantum information processing systems.
We present results of a bright polarization-entangled photon source operating at 1552 nm via type-II collinear degenerate spontaneous parametric down-conversion in a periodically poled potassium titanyl phosphate crystal. We report a conservative inferred pair generation rate of 123,000 pairs/s/mW into collection modes. Minimization of spectral and spatial entanglement was achieved by group velocity matching the pump, signal, and idler modes and through properly focusing the pump beam. By utilizing a pair of calcite beam displacers, we are able to overlap photons from adjacent down-conversion processes to obtain polarization-entanglement visibility of 94.7+/-1.1% with accidentals subtracted.
We demonstrate efficient generation of collinearly propagating, degenerate pulsed photon pairs based on a bulk periodically poled potassium titanyl phosphate pumped by an ultrashort-pulse laser. Using a single-mode fiber as a spatial mode filter, we detect approximately 3200 coincidence counts per second per milliwatt pump power in a Hanbury–Brown–Twiss-type experiment. The estimated photon-pair production rate is approximately 1.05 MHz/mW pump power. This is very promising for the realization of sources for quantum communication and metrology.
We demonstrate a polarization-entangled photon-pair source obtained via a type-II non-collinear quasi-phase-matched spontaneous parametric down-conversion process with a 10-mm periodically poled KTiOPO4 crystal, which is as stable and wavelength-tunable as the well-known Sagnac configuration scheme. A brightness of 4.2 kHz/mW is detected and a concurrence of 0.975 is estimated using quantum state tomography. Without loss of entanglement and brightness, the photon-pair wavelengths are tunable through control of the crystal temperature. This improvement is achieved using the non-collinear configuration and a stable interferometric distinguishability compensator.