Fabrication of whispering gallery mode cavity using crystal growth

TL;DR

This paper presents a novel laser-heated pedestal growth method for fabricating crystalline whispering gallery mode cavities, achieving high Q factors and demonstrating control over cavity shape without damaging crystal quality.

Contribution

The authors introduce a new fabrication technique for sapphire whispering gallery mode cavities that allows shape control and high Q factors through growth condition adjustments.

Findings

Achieved a Q factor of 16000 in sapphire cavities

Controlled cavity shape by adjusting growth conditions

Maintained crystal integrity during fabrication

Abstract

We developed a new method for fabricating crystalline whispering gallery mode cavities based on laser-heated pedestal growth. We fabricated sapphire cavities and obtained a Q factor of 16000 with a cavity whose diameter was about 240 um. We showed numerically that the cross-sectional shape of the cavity is sensitive to the cavity Q, and we controlled it successfully by changing the growth condition in the molten zone, without significantly degrading the crystal structure.