Rayleigh scattering boosted multi-GHz displacement sensitivity in whispering gallery opto-mechanical resonators

TL;DR

This paper introduces a novel high-bandwidth displacement sensing method using Rayleigh scattering in photonic resonators, achieving efficient modulation at frequencies up to 9.1 GHz, surpassing traditional bandwidth limits.

Contribution

The work presents a new displacement sensing scheme leveraging Rayleigh scattering, enabling high-frequency operation independent of drive mechanism, compatible with various transduction techniques.

Findings

Achieved displacement modulation at 9.1 GHz.

Demonstrated independence from specific drive mechanisms.

Enhanced bandwidth beyond photon lifetime limitations.

Abstract

Finite photon lifetimes for light fields in an opto-mechanical cavity impose a bandwidth limit on displacement sensing at mechanical resonance frequencies beyond the loaded cavity photon decay rate. Opto-mechanical modulation efficiency can be enhanced via multi-GHz transduction techniques such as piezo-opto-mechanics at the cost of on-chip integration. In this paper, we present a novel high bandwidth displacement sense scheme employing Rayleigh scattering in photonic resonators. Using this technique in conjunction with on-chip electrostatic drive in silicon enables efficient modulation at frequencies up to 9.1GHz. Being independent of the drive mechanism, this scheme could readily be extended to piezo-opto-mechanical and all optical transduced systems.