Proposal of Rydberg atomic receiver for amplitude-modulated microwave signals with active Raman gain

An efficient scheme for a microwave (MW) receiver is proposed based on the active Raman gain (ARG) in Rydberg atoms. The ⁸⁷Rb atoms are excited to the Rydberg state (53D_5/2), and the gain spectrum has a single gain peak. The MW field is resonant with the Rydberg transition (53D_5/2→54P_3/2), resulting in a split in the gain spectrum. The frequency splitting of two peaks depends linearly on the MW field strength. The distortion and attenuation of the probe field are reduced, due to the system's operating in the stimulated Raman emission mode. Simulation results show that the fidelity of MW communication based on the Rydberg atomic ARG scheme is improved by at least 10 times compared to that based on an electromagnetically induced transparency scheme, and the system seems more robust to amplitude modulation signals with different modulation depths.