Shaping Temporal Correlation of Biphotons in a Hot Atomic Ensemble

Abstract

The biphoton states have served as one of the candidates for most quantum‐enabled technologies. Moreover, with the benefit of photon–atom interactions, biphotons with controllable wave functions are particularly interesting in quantum information processes. Herein, an experimental realization of the shaping temporal correlation of biphotons from the four‐wave mixing process in a hot Rb atomic ensemble is presented. Based on the slow‐light effect and electromagnetically induced transparency in the group delay region, the precursor‐like propagation is observed and separated from the rising edge of the delayed wave packets of biphotons temporal correlation. In addition, the application of an additional dressing field enriches the features of the biphotons temporal correlation such as the manipulation of the dispersion experienced by the generated photons and controllable coherent time. Furthermore, with a higher optical depth and stronger dressing coupling effect, the temporal correlation of biphotons is shaped from the group delay region to the Rabi oscillation region and even superposed of them.