Bandwidth-Dependent and Other Types of Two-Photon Quantum Correlations in Parametric Down Conversion

Roger Andrews, Andrea T. Joseph, Edward R. Pike +1 more

Sarben Sarkar, R. A. Andrews, E R Pike

Yanhua H. Shih, Alexander V. Sergienko, Morton H. Rubin +2 more

We present an experimental study of the entangled two-photon polarization states in type-II optical parametric down-conversion. It is interesting to see that the polarization entanglement depends on the detection spectral bandwidth, i.e., the bandwidth of the spectral filters placed in front of the detectors. The entanglement is also dependent on the length of the down-conversion crystal. A simple quantum model is provided to explain these phenomena.

Chung Ki Hong

Alejandra Valencia, Alessandro Ceré, X. Shi +3 more

The bandwidth and the frequency correlations of quantum light can be considered as a resource for the implementation of new quantum information algorithms, and it should enable the applicability of quantum techniques not yet implemented. For that purpose, the control of the frequency correlations, and the bandwidth, of single and paired photons is an essential ingredient, since the optimum bandwidth, as well as the most appropriate type of frequency correlations for a specific quantum application, depend on the specific quantum information application under consideration. Here we elucidate and implement new strategies to tailor the frequency properties of quantum light. Such strategies, which are based on the use of non collinear spontaneous parametric down conversion (SPDC) configurations, include the generation of narrow and enhanced bandwidth quantum light, the control of the frequency correlations of paired photon, and the generation of heralded single photons with a high degree of purity from pairs of uncorrelated photons.

Thomas E. Kiess, Yanhua H. Shih, Alexander V. Sergienko +1 more

We report a new two-photon polarization correlation experiment for realizing the Einstein-Podolsky-Rosen-Bohm (EPRB) state and for testing Bell-type inequalities. We use the pair of orthogonally polarized light quanta generated in type-II parametric down-conversion. In a 1 nm bandwidth, we observe from the output of a 0.5 mm \ensuremath{\beta}-${\mathrm{BaB}}_{2}$${\mathrm{O}}_{4}$ crystal the EPRB correlations in coincidence counts, and measure an associated Bell inequality violation of 22 standard deviations.