GaN/AlGaN microcavities for enhancement of non linear optical effects

TL;DR

This paper investigates GaN/AlGaN microcavities to enhance second order nonlinear optical effects, focusing on design, growth, and optical characterization to improve nonlinear response for near UV applications.

Contribution

It introduces a novel GaN/AlGaN microcavity structure optimized for second harmonic generation, emphasizing growth quality and interface sharpness to boost nonlinear effects.

Findings

Enhanced second harmonic generation in microcavity compared to bulk GaN

High quality factor achieved through optimized layer growth

Microcavity design significantly improves nonlinear optical response

Abstract

We present a study on the design, growth and optical characterization of a GaN/AlGaN microcavity for the enhancement of second order non linear effects. The proposed system exploits the high second order nonlinear optical response of GaN due to the non centrosymmetric crystalline structure of this material. It consists of a GaN cavity embedded between two GaN/AlGaN Distributed Bragg Reflectors designed for a reference mode coincident with a second harmonic field generated in the near UV region (~ 400 nm). Critical issues for this target are the crystalline quality of the material, together with sharp and abrupt interfaces among the multi-stacked layers. A detailed investigation on the growth evolution of GaN and AlGaN epilayers in such a configuration is reported, with the aim to obtain high quality factor in the desiderated spectral range. Non linear second harmonic generation experiments have been performed and the results were compared with bulk GaN sample, highlighting the effect of the microcavity on the non linear optical response of this material.