Broadband Rydberg Atomic Microwave Sensing with 44.6MHz Instantaneous Bandwidth

Abstract

Rydberg atoms have become a promising novel type of microwave sensor due to their excellent physical properties -- broad frequency coverage and large electric dipole moments. High sensitivity and broad instantaneous bandwidth are two indispensable requirements for deployable Rydberg microwave sensors. However, enabling broadband operation while retaining high sensitivity has been a longstanding barrier limiting their applications. We propose and experimentally demonstrate a Rydberg microwave sensor whose instantaneous bandwidth is significantly enhanced via an auxiliary microwave field. By finely modulating the Rydberg energy levels with this field, we broaden the bandwidth substantially while retaining the sensor's inherent high sensitivity. An instantaneous bandwidth of 44.6MHz ($\pm$22.3MHz) with a sensitivity of 225.7nVcm${}^{-1}$Hz${}^{-1/2}$ is realized in a thermal \(^{87}\)Rb vapor with the local microwave frequency of 16.03GHz. Our work delivers concurrent broad instantaneous bandwidth and high sensitivity for Rydberg microwave sensors, paving a technically viable path for their practical deployment in broadband microwave metrology, radar, and wireless communication.

8 pages, 5 figures