Laser-Machined Ultra-High-Q Microrod Resonators for Nonlinear Optics

TL;DR

This paper introduces a rapid fabrication method for ultra-high-Q fused-quartz microresonators using CO2-laser machining, enabling low-threshold nonlinear optical phenomena like Raman and Brillouin scattering.

Contribution

It presents a fast, efficient fabrication process for ultra-high-Q whispering-gallery-mode resonators with demonstrated nonlinear optical capabilities.

Findings

Resonators with Q > 10^9 were achieved.

Fabrication time is less than one minute.

Multiple nonlinear effects observed, including Raman and Brillouin scattering.

Abstract

Optical whispering-gallery microresonators are useful tools in microphotonics, and nonlinear optics at very low threshold powers. Here, we present details about the fabrication of ultra-high-Q whispering-gallery-mode resonators made by CO2-laser lathe machining of fused-quartz rods. The resonators can be fabricated in less than one minute and the obtained optical quality factors exceed Q = 10^9. Demonstrated resonator diameters are in the range between 170 {\mu}m and 8 mm (free spectral ranges between 390 GHz and 8 GHz). Using these microresonators, a variety of optical nonlinearities are observed, including Raman scattering, Brillouin scattering and four-wave mixing.