Correlated photon pairs generated from a warm atomic ensemble

Abstract

We present measurements of the cross-correlation function of photon pairs at 780 nm and 1367 nm, generated in a hot rubidium vapor cell. The temporal character of the biphoton is determined by the dispersive properties of the medium where the pair generation takes place. We show that short correlation times occur for optically thick samples, which can be understood in terms of offresonant pair generation. By modifying the linear response of the sample, we produce near-resonant photon pairs, which could in principle be used for entanglement distribution.

Nonclassical photon pairs from warm atomic vapor using a single driving laser

“…Compared to the recent realizations of nonclassical sources with warm atomic vapors [14,[17][18][19][20], the overall experimental scheme has been strongly simplified. Using the single excitation laser not only reduces the complexity and spatial demands of the whole experiment, but also allows for simple alignment of the spatial phasematching in of SFWM process.…”

“…In the case of employing the double-Λ energy level scheme where frequencies of interacting photons are nearly degenerate, the correlated photons are radiated close to exactly opposite directions. The use of the single excitation laser in retro-reflected configuration then allows for easy alignment of the whole setup without any need for auxiliary seed beams as in schemes employing several different wavelengths of absorbed and emitted photons [18,20]. The frequency difference of ∆ν S,AS = 13.6 GHz between Stokes and anti-Stokes photons together with the cancellation of the excitation laser momenta in the back-reflection excitation configuration leads to the residual phase mismatch of the realized SFWM process.…”

Direct observation of broadband nonclassical states in a room-temperature light–matter interface

“…The previous experiments with small detuning in room-temperature atoms suffer from fluorescence noise induced by Doppler effect and atom-atom collision. The broadband nonclassical correlation can be observed by continuously addressing ladder-type hot atoms, which is, however, not directly usable due to the random creation time of correlated photons and the distinctly different interaction mechanism with Raman process of broadband quantum memory [29,30].…”

Continuous-wave four-wave mixing in a single-mode tellurite fiber

“…[1][2][3][4][5] It leads to many applications, such as wavelength converters, optical demultiplexers, optical parametric amplification (OPA), quantum information processing, and correlated photons pairs generation. [6][7][8][9][10][11][12] A high efficiency in FWM depends crucially on the nonlinear phase-matching (PM) condition which can be easily achieved in the vicinity of the zero-dispersion wavelength (ZDW) or anomalous chromatic dispersion regime. 13,14 Up to now, a lot of works on FWM have been demonstrated based on fibers with various structures and different materials.…”