Intermodulation of optical frequency combs in a multimode optomechanical system

TL;DR

This paper demonstrates a multimodal optomechanical system where two mechanical modes generate intermodulated optical frequency combs, enabling control of multiple mechanical degrees of freedom for advanced signal processing and sensing.

Contribution

It introduces a novel multimodal optomechanical platform with simultaneous phonon lasing at MHz and GHz frequencies, leading to intermodulation of optical frequency combs.

Findings

Successful excitation of mechanical modes at 265 MHz and 6.8 GHz into phonon lasing regimes

Observation of self-sustained oscillations in both MHz and GHz modes

Experimental demonstration of intermodulation of optical frequency combs

Abstract

Phonons offer the possibility to connect the microwave and optical domains while being efficiently transduced with electronic and optical signals. Here, we present a multimodal optomechanical platform, consisting of a mechanical-optical-mechanical resonator configuration. The mechanical modes, with frequencies at 265 MHz and 6.8 GHz, can be simultaneously excited into a phonon lasing regime as supported by a stability analysis of the system. Both the MHz and the GHz modes enter a self-sustained oscillation regime, leading to the intermodulation of two frequency combs in the optical field. We characterize this platform experimentally, demonstrating previously unexplored dynamical regimes. These results suggest the possibility to control multiple mechanical degrees of freedom via a single optical mode, with implications in GHz phononic devices, signal processing, and optical comb sensing applications.