Cascaded forward Brillouin lasing in a chalcogenide whispering gallery mode microresonator

TL;DR

This paper reports the first observation of cascaded forward stimulated Brillouin scattering in a microresonator, demonstrating multiple Stokes beams with low threshold, supported by theoretical modeling, advancing integrated photonics applications.

Contribution

First experimental demonstration of cascaded forward stimulated Brillouin scattering in a microresonator platform with theoretical support.

Findings

25 orders of Stokes beams observed

Brillouin shift of 34.5 MHz at low threshold

Supported by theoretical modeling

Abstract

We report the first observation of cascaded forward stimulated Brillouin scattering in a microresonator platform. We have demonstrated 25 orders of intramodal Stokes beams separated by a Brillouin shift of 34.5 MHz at a sub-milliwatt threshold at 1550 nm. An As$_2$S$_3$ microsphere of diameter 125 $\mu m$ with quality factor $1\times 10^6$ was used for this demonstration. Theoretical modeling is used to support our experimental observations of Brillouin shift and threshold power. We expect our work will advance the field of forward stimulated Brillouin scattering in integrated photonics with applications in gas sensing and photonic radio frequency sources.