Fast Detection of Multi‐Period Microwave Pulses in Rydberg‐Atom Mixer

A scheme for the fast detection of multi‐period microwave (MW) pulses is proposed in a four‐level Rydberg‐atom system via electromagnetically induced transparency (EIT). Rydberg‐atom EIT shows a transparency window with coupling of a probe and a control lasers. When the Rydberg atoms are irradiated by a MW field, the output pulse experiences serious time delay due to the medium dispersion. It is interesting to find that the time delay is much reduced when we use a relatively strong probe field. The simulation result indicates that the average time delay of the pulse series can be reduced to 0.32 , which is about 1/8 of that in a single pulse detection. In this case, the nonlinear dispersion leads to fast detection of the pulse's wavefront. For the following pulses, the fast detection is attributed to the Kerr nonlinearity and atomic population dynamics. Moreover, its delay reduction ratio could reach up to 87.2%. The impacts of pulse durations, intervals, and thermal perturbations are also investigated and the scheme shows good robustness.