Analog phase-sensitive time-reversal of optically-carried radiofrequency signals

Abstract

Achieving low-latency time-reversal of broadband radiofrequency signals is crucial for reliable communications in dynamic, uncontrolled environments. However, existing approaches are either digitally assisted -- making broadband extension challenging -- or limited to amplitude modulation. In this work, we report the very first experimental realization of a fully analog, phase-preserving time-reversal architecture for optically-carried radiofrequency signals. The method exploits the exceptional coherence properties of rare-earth ion-doped materials, and leverages the well-established photon echo mechanism, widely used in quantum technologies. While our demonstration is conducted with a modest bandwidth, we identify the fundamental cause of this limitation and propose solutions for future scalability.