Optically-biased Rydberg microwave receiver enabled by hybrid nonlinear interferometry.

Borówka, Sebastian; Mazelanik, Mateusz; Wasilewski, Wojciech; Parniak, Michał · Nat Commun · 2025

basic_science · Level V

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Abstract

Coupling a Rydberg vapour medium to both microwave and optical fields enables the benefits of all-optical detection, such as minimal disturbance of the measured field and resilience to very strong signals, since no conventional antenna is required. However, peak sensitivity typically relies on adding a microwave local oscillator, which compromises the all-optical nature of the measurement. Here we introduce an alternative, optical-bias detection, that maintains fully optical operation while achieving high sensitivity. To address laser phase noise, which is critical in this approach, we perform a simultaneous measurement of the noise using a nonlinear process and correct it in real time via data processing. This yields a 35 dB improvement in signal-to-noise ratio compared with the basic method. We demonstrate a sensitivity of <math xmlns="http://www.w3.org/1998/Math/MathML"><mn>176</mn> <mspace></mspace> <mi>nV</mi> <mo>/</mo> <mi>cm</mi> <mo>/</mo> <msqrt><mrow><mi>Hz</mi></mrow> </msqrt> </math> , reliable operation up to 3.5 mV/cm at 13.9 GHz, and quadrature-amplitude modulated data transmission, underlining the ability to detect microwave field quadratures while preserving the unique advantages of all-optical detection.