Broadband tunable ultra-compact resonator enhanced Rydberg atomic sensor

In this article, we propose a tunable multilayered resonator (TMR) to achieve broadband high-sensitivity sensing within a deep-subwavelength structure. The proposed TMR significantly enhances the incident electric field for Rydberg atoms, improving the sensitivity of the room-temperature atomic sensor. Additionally, by incorporating varactor diodes, the resonant frequency of the TMR can be dynamically controlled by adjusting the diode bias voltage. In the experiment, the TMR realized a 45.26% relative bandwidth, ranging from 13.19 MHz to 19.16 MHz. Furthermore, the sensitivity of the system reached 0.13 µV/cm/Hz in the presence of the TMR at 19.16 MHz, compared to only 24.59 µV/cm/Hz without the TMR.