A full free spectral range tuning of p-i-n doped Gallium Nitride microdisk cavity

TL;DR

This paper demonstrates a method for permanently tuning the whispering gallery modes of p-i-n doped GaN microdisk cavities over a full free spectral range using UV laser irradiation in water, advancing nanophotonic device control.

Contribution

It introduces a novel UV laser tuning technique for GaN microdisks that achieves full spectral range tuning through surface etching, enabling precise control for quantum electrodynamics applications.

Findings

Tuning rate varies linearly with laser power.

Surface etching is the primary mechanism for mode shift.

Achieved full free spectral range tuning.

Abstract

Effective, permanent tuning of the whispering gallery modes (WGMs) of p-i-n doped GaN microdisk cavity with embedded InGaN quantum dots over one free spectral range is successfully demonstrated by irradiating the microdisks with a ultraviolet laser (380nm) in DI water. For incident laser powers between 150 and 960 nW, the tuning rate varies linearly. Etching of the top surface of the cavity is proposed as the driving force for the observed shift in WGMs, and is supported by experiments. The tuning for GaN/InGaN microdisk cavities is an important step for deterministically realizing novel nanophotonic devices for studying cavity quantum electrodynamics.