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Related papers: Polarization Entanglement from Parametric Down-Con…

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Polarization-entangled photon pairs can be efficiently prepared into pure Bell states with a high fidelity via type-II spontaneous parametric down-conversion (SPDC) of narrow-band pump light. However, the use of femtosecond pump pulses to…

Quantum Physics · Physics 2007-05-23 Hou Shun Poh , Chune Yang Lum , Ivan Marcikic , Antia Lamas-Linares , Christian Kurtsiefer

Generating nonclassical states of photons such as polarization entangled states on a monolithic chip is a crucial step towards practical applications of optical quantum information processing such as quantum computing and quantum key…

Quantum Physics · Physics 2021-12-30 Dongpeng Kang , Minseok Kim , Haoyu He , Amr S. Helmy

The influence of pump coherence on the entanglement produced in spontaneous parametric down-conversion (SPDC) is important to understand, both from a fundamental perspective, and from a practical standpoint for controlled generation of…

Quantum Physics · Physics 2023-04-13 Cheng Li , Boris Braverman , Girish Kulkarni , Robert W. Boyd

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.…

We experimentally demonstrate a violation of local realism with highly spatially multimode polarization-entangled two-photon states produced by spontaneous parametric down-conversion (SPDC) pumped by a spatially incoherent light source-a…

Quantum Physics · Physics 2025-12-01 Cheng Li , Jeremy Upham , Boris Braverman , Robert W. Boyd

Two-photon states generated from spontaneous parametric down-conversion (SPDC) can display entanglement in all degrees of freedom (DoFs) of light, including spatial, temporal, and polarization. The coupling between different DoFs of a…

Energy consumption is becoming a serious bottleneck for integrating quantum technologies within the existing global information infrastructure. In photonic architectures, considerable energy overheads stem from using lasers, whose high…

Quantum Physics · Physics 2026-05-19 Cheng Li , Jasvinder Brar , Michael Küblböck , Jeremy Upham , Hanieh Fattahi , Robert W. Boyd

We demonstrate experimental generation of spatially-entangled photon-pairs by spontaneous parametric down conversion (SPDC) using a partial spatially coherent pump beam. By varying the spatial coherence of the pump, we show its influence on…

Quantum Physics · Physics 2019-05-29 Hugo Defienne , Sylvain Gigan

We present theoretical and experimental study of preparing maximally entangled two-photon polarization states, or Bell states, using femtosecond pulse pumped spontaneous parametric down-conversion (SPDC). First, we show how the inherent…

Quantum Physics · Physics 2009-11-07 Yoon-Ho Kim , Maria V. Chekhova , Sergei P. Kulik , Morton H. Rubin , Yanhua Shih

This manuscript presents a method to convert position correlation of photon-pairs into polarization entanglement. This is achieved by individually manipulating the polarization state of photons generated in different parts of a non-linear…

Quantum Physics · Physics 2020-07-15 Chithrabhanu Perumangatt , Alexander Lohrmann , Alexander Ling

We develop and experimentally verify a theory of Type-II spontaneous parametric down-conversion (SPDC) in media with inhomogeneous distributions of second-order nonlinearity. As a special case, we explore interference effects from SPDC…

Spontaneous parametric down-conversion (SPDC) is the most widely used process for generating entangled photon pairs. In SPDC, a pump photon interacts with a nonlinear optical crystal and splits into two entangled photons called the signal…

A new method for generating entangled photons with controllable frequency correlation via spontaneous parametric down-conversion (SPDC) is presented. The method entails initiating counter-propagating SPDC in a single-mode nonlinear…

We have experimentally created a robust, ultrabright and phase-stable polarization-entangled state close to maximally entangled Bell-state with $ \% 98 $-fidelity using the type-II spontaneous parametric down-conversion (SPDC) process in…

Quantum Physics · Physics 2021-07-05 Ali Motazedifard , Seyed Ahmad Madani , J. Jafari Dashkasan , N. Sobhkhiz Vayaghan

We study the frequency-angular lineshape for a phase-matched nonlinear process producing entangled states and show that there is a continuous variety of maximally-entangled states generated for different mismatch values within the natural…

Quantum Physics · Physics 2015-05-13 G. Brida , M. V. Chekhova , M. Genovese , L. A. Krivitsky

We implement experimentally a method to generate photon-number$-$path and polarization entangled photon pairs using ``beamlike'' type-II spontaneous parametric down-conversion (SPDC), in which the signal-idler photon pairs are emitted as…

Quantum Physics · Physics 2009-11-10 Yoon-Ho Kim

In this letter, we study spontaneous parametric down-conversion (SPDC) in a periodically poled structure composed of two linearly uncoupled resonators that are nonlinearly coupled via a Mach-Zehnder interferometer. The device does not…

Optics · Physics 2024-06-27 Alessia Stefano , Luca Zatti , Marco Liscidini

Entanglement enables many promising applications in quantum technology. Devising new generation methods and harnessing entanglement are prerequisites for practical applications. Here we realize a distinct polarization-entangled source by…

Quantum Physics · Physics 2024-02-29 Ming-Yuan Gao , Yin-Hai Li , Zhao-Qi-Zhi Han , Qiang Zhou , Guang-Can Guo , Zhi-Yuan Zhou , Bao-Sen Shi

It is shown, theoretically and experimentally, that at any type-II spontaneous parametric down-conversion (SPDC) phase matching, the decoherence-free singlet Bell state is always present within the natural bandwidth and can be filtered out…

Quantum Physics · Physics 2007-10-01 G. Brida , M. V. Chekhova , M. Genovese , L. A. Krivitsky

The photon-pairs generated through spontaneous parametric down-conversion (SPDC) possess strong correlations in their transverse position and momentum degrees of freedom. For such photon pairs, the transverse position correlation length…

Quantum Physics · Physics 2022-12-14 Satyajeet Patil , Shashi Prabhakar , Ayan Biswas , Ashok Kumar , R. P. Singh
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