Microwave Power-to-Frequency Transduction via Injection Pulling of a Self-Sustained Oscillator for Rydberg Superheterodyne Sensing

TL;DR

This paper demonstrates a novel microwave power-to-frequency transduction method using a self-sustained oscillator coupled with Rydberg atom sensing, enabling optical readout of microwave signals through injection pulling dynamics.

Contribution

It introduces a Rydberg superheterodyne sensing architecture that converts microwave power into frequency shifts via injection pulling of a self-sustained oscillator.

Findings

Achieved a peak responsivity of 35 kHz/dB.

Demonstrated continuous IF tuning with input power.

Observed Adler-type injection-pulling behavior.

Abstract

A Rydberg superheterodyne sensing architecture is demonstrated in which a self-sustained oscillator (SSO) serves as a dynamically perturbed local oscillator (LO) for microwave detection. The SSO is realized by a phase-controlled radio-frequency (RF) feedback loop coupled to a transverse electromagnetic (TEM) cavity containing a Rydberg vapor cell. The system operates near 5.49 GHz using a cesium ladder scheme with an 852 nm probe and 510 nm coupling laser addressing the 6S to 6P to 49D transition, with microwave coupling to the 50P state. Injection of a microwave signal pulls the SSO frequency via nonlinear dynamics, converting input power into a measurable frequency shift read out optically as a Rydberg probe intermediate-frequency (IF) signal. The response follows Adler-type injection-pulling behavior, with continuous IF tuning with input power. A peak responsivity of 35 kHz/dB is observed, with enhanced sensitivity near synchronization. These results demonstrate power-to-frequency transduction using a dynamically perturbed LO combined with Rydberg atomic readout.