Surface Acoustic Wave Frequency Comb

TL;DR

This paper demonstrates the generation of a surface acoustic wave frequency comb through nonlinear opto-mechanical interactions in a crystalline resonator, enabling new possibilities for precise acoustic and optical control.

Contribution

It introduces a novel triply-resonant coupling mechanism that produces a SAW frequency comb via hyper-parametric oscillation in a whispering gallery mode resonator.

Findings

Successful generation of a SAW frequency comb.

Visualization of the comb through light modulation.

Observation of mechanical hyper-parametric oscillation.

Abstract

We report on realization of an efficient triply-resonant coupling between two long lived optical modes and a high frequency surface acoustic wave (SAW) mode of the same monolithic crystalline whispering gallery mode resonator. The coupling results in an opto-mechanical oscillation and generation of a monochromatic SAW. A strong nonlinear interaction of this mechanical mode with other equidistant SAW modes leads to mechanical hyper-parametric oscillation and generation of a SAW pulse train and associated frequency comb in the resonator. We visualized the comb observing the modulation of the modulated light escaping the resonator.