Related papers: Four-photon correction in two-photon Bell experime…
In a recent article [Phys. Rev. Lett. 133, 033601 (2024)], the coherence time of degenerate entangled photon pairs (biphotons) generated via backward spontaneous four-wave mixing in a cold atomic ensemble was shown to be immune to optical…
In the process of spontaneous parametric downconversion, photons from a pump field are converted to signal and idler photon pairs in a nonlinear crystal. The reversed process, or upconversion of these pairs back to single photons in a…
Sources of photon pairs based on the spontaneous parametric down conversion process are commonly used for long distance quantum communication. The key feature for improving the range of transmission is engineering their spectral properties.…
A quantum system composed of two or more subsystems can be in an entangled state, i.e. a state in which the properties of the global system are well defined but the properties of each subsystem are not. Entanglement is at the heart of…
A method for preparing a loophole-free four-photon Bell experiments which requires a detection efficiency of 67% is proposed. It enables realistic detection efficiencies of 75% at a visibility of 85%. Two type-II crystals each down convert…
We report the first entanglement generation experiment using an on-chip slow light device. With highly efficient spontaneous four-wave mixing enhanced by the slow light effect in a coupled resonator optical waveguide based on a silicon…
If identical photons meet at a semi-transparent mirror they appear to leave in the same direction, an effect called "two-photon interference". It has been known for some time that this effect should occur for photons generated by dissimilar…
Advanced quantum networking protocols beyond bi-photon, point-to-point links rely critically on the ability to perform multi-photon interference across multiple nodes under realistic operating conditions. Yet experimental validation of such…
High-visibility quantum interference between independent photons is essential for demonstrating multi-photon quantum information processing, and it is closely linked to the spectral purity of correlated photon pairs. In this study, we…
We report a two-photon interference effect, in which the entangled photon pairs are generated from two laser pulses well-separated in time. In a single pump pulse case, interference effects did not occur in our experimental scheme. However,…
We study the interference structure of the second-order intensity correlation function for polarization-entangled two-photon light obtained from type-II collinear frequency-degenerate spontaneous parametric down-conversion (SPDC). The…
The dependence of one- and two-photon characteristics of pulsed entangled two-photon fields generated in spontaneous parametric down-conversion on the pump-pulse properties (shape of the pump-pulse spectrum and its internal structure) is…
When two-photon interactions are induced by down-converted light with a bandwidth that exceeds the pump bandwidth, they can obtain a behavior that is pulse-like temporally, yet spectrally narrow. At low photon fluxes this behavior reflects…
Quantum networks involve entanglement sharing between multiple users. Ideally, any two users would be able to connect regardless of the type of photon source they employ, provided they fulfill the requirements for two-photon interference.…
We report the observation of symmetry protected two-photon coherence time of biphotons generated from backward spontaneous four-wave mixing in laser-cooled $^{87}$Rb atoms. When biphotons are nondegenerate, non-symmetric photonic absorption…
We demonstrate suppression and enhancement of spontaneous parametric down- conversion via quantum interference with two weak fields from a local oscillator (LO). Pairs of LO photons are observed to upconvert with high efficiency for…
In this report the decoherence sources for entangled photons created by spontaneous parametric down conversion phenomenon is studied. The phase and spatial distinguishability of photon pairs from orthogonal crystals reduce the maximum…
Two-photon interference effects, such as the Hong-Ou-Mandel (HOM) effect, can be used to characterize to what extent two photons are identical. Identical photons are necessary for both linear optics quantum computing and single-photon…
We study the polarization dependent second order correlation of a pair of photons emitted in a four level radiative cascade driven by an external field. It is found that the quantum correlations of the emitted photons, degraded by the…
Quantum entanglement plays a vital role in many quantum information and communication tasks. Entangled states of higher dimensional systems are of great interest due to the extended possibilities they provide. For example, they allow the…