Deep-subwavelength Resonator Based Rydberg Atomic Receiver for HF Band Enhanced Sensing

In this article, we propose a new paradigm of room-temperature Rydberg atomic receiver for high frequency (HF) band sensing with high sensitivity. The proposed Rydberg atomic HF band receiver is implemented via a multilayered split-ring resonator (MSRR) and an atomic vapor cell. The MSRR is constructed by a five-layered printed circuit board within a deep-subwavelength size, providing a strongly enhanced electric field of the incident radio-frequency (RF) field. Using a quantum-optical readout of AC level shifts of field-sensitive atomic Rydberg states, the enhanced intra-cavity RF field significantly improves the sensitivity of the atomic receiver. In the measurement, we characterize the AC-stark shift in the frequency and power spectrum of the incident RF field. Furthermore, the sensitivity of the whole system is presented by utilizing the off-resonant Rydberg atomic heterodyne technique. In the absence of the MSRR, the sensitivity for an RF signal at 20.51 MHz was found to be 27.46 μV/cm √Hz. However, with the presence of our MSRR, the sensitivity significantly improved to 29.09 nV/cm √Hz, indicating a remarkable enhancement capacity of 944 times or 60 dB. This research holds great potential for high-sensitivity Rydberg atomic sensing, particularly in the HF band.