Controlled tuning of whispering gallery modes of GaN/InGaN microdisk cavities

TL;DR

This paper demonstrates room-temperature control of whispering gallery modes in GaN/InGaN microdisk cavities using water immersion and UV laser irradiation, with precise tuning enabled by adjusting laser power.

Contribution

It introduces a novel method for tuning WGMs in GaN/InGaN microdisks at room temperature through UV laser irradiation and water immersion, supported by theoretical analysis.

Findings

Tuning of WGMs achieved at room temperature.

Tuning rate controlled by laser power with nanometer precision.

Proposed selective oxidation mechanism explains the tuning process.

Abstract

Controlled tuning of the whispering gallery modes of GaN/InGaN {\mu}-disk cavities is demonstrated. The whispering gallery mode (WGM) tuning is achieved at room temperature by immersing the {\mu}-disks in water and irradiating with ultraviolet (UV) laser. The tuning rate can be controlled by varying the laser excitation power, with a nanometer precision accessible at low excitation power (~ several {\mu}W). The selective oxidation mechanism is proposed to explain the results and supported by theoretical analysis. The tuning of WGMs in GaN/InGaN {\mu}-disk cavities may have important implication in cavity quantum electrodynamics and the development of efficient light emitting devices.