Significant progress has been made in the research on the detection of microwave electric fields in the Rydberg area of Shanghai Institute of Optics and Technology

Recently, the Aerospace Laser Technology and System Department of the Shanghai Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, and the East China Research Team of the Key Laboratory of Quantum Optics, Chinese Academy of Sciences, together with the research team of Professor Chen Liqing of East China Normal University, demonstrated a Rydberg microwave sensor with high sensitivity and high instantaneous bandwidth for the first time in rubidium Rydberg atoms. The related achievements are titled "Highly sensitive microwave electronics with enhanced instantaneous bandwidth" and published in the PHYSICAL VIEW APPLED (Letter).

Rydberg atoms are highly excited atoms with a large electric dipole moment and are highly sensitive to external electromagnetic fields. Therefore, it has been proposed to use the electromagnetic induced transparency (EIT) and Autler Townes (AT) effects of Rydberg atoms to measure microwave electric fields. The detection sensitivity and instantaneous bandwidth are key indicators for Rydberg microwave detection. Previously, based on Rydberg atomic superheterodyne detection technology, high sensitivity (55 nV cm? 1 Hz? 1/2) could be achieved, but its instantaneous bandwidth was limited to several hundred kilohertz. Having both high sensitivity and large instantaneous bandwidth is a challenge in the research field of Rydberg microwave electric field detection.

Based on six wave mixing technology, the research team experimentally demonstrated a Rydberg microwave sensor that achieves both high sensitivity and high instantaneous bandwidth in a rubidium Rydberg atomic gas chamber. With an instantaneous bandwidth of up to 10.2 MHz, the maximum detection sensitivity can reach 62nVcm-1Hz-1/2. Theoretical and experimental results indicate that the enhanced high-frequency response comes from the enhancement effect of the detection light negative sideband generated by the six wave mixing process. The research results will promote the application of Rydberg microwave sensing technology in radar and communication.

The related work has been supported by projects such as the National Natural Science Foundation of China.

Figure 1 Schematic diagram of the experimental setup for the principle (a) of the Rydberg microwave sensor

(b) (c) Two six wave mixing processes that generate positive and negative sidebands

Figure 2 Sensitivity of Rydberg Microwave Sensor (a) Relationship between Superheterodyne Signal and Signal Microwave Power (b) Sensitivity Determined by System Noise

Source: Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences