Two-photon beating experiment using biphotons generated from a two-level system

Physics Department, University of Virginia, Charlottesville, Virginia 22904, USA(Dated: July 25, 2008)We propose a two-photon beating experiment based upon biphotons generated from a resonantpumping two-level system operating in a backward geometry. On the one hand, the linear optical-response leads biphotons produced from two sidebands in the Mollow triplet to propagate withtunable refractive indices, while the central-component propagates with unity refractive index. Therelative phase difference due to different refractive indices is analogous to the pathway-length differ-ence between long-long and short-short in the original Franson interferometer. By subtracting thelinear Rayleigh scattering of the pump, the visibility in the center part of the two-photon beatinginterference can be ideally manipulated among [0, 100%] by varying the pump power, the materiallength, and the atomic density, which indicates a Bell-type inequality violation. On the other hand,the proposed experiment may be an interesting way of probing the quantum nature of the detectionprocess. The interference will disappear when the separation of the Mollow peaks approaches thefundamental timescales for photon absorption in the detector.