Gallium nitride L3 photonic crystal cavities with an average quality factor of 16,900 in the near infrared

TL;DR

This paper reports the fabrication and optimization of GaN L3 photonic crystal cavities with high quality factors averaging 16,900, demonstrating their potential for near-infrared photonic applications.

Contribution

The study introduces an automated genetic algorithm-based optimization of GaN L3 photonic crystal cavities achieving record high quality factors.

Findings

Average Q factor of 16,900 achieved

Maximum measured Q of 22,500

Results align with first-principles simulations

Abstract

Photonic crystal point-defect cavities were fabricated in a GaN free-standing photonic crystal slab. The cavities are based on the popular L3 design, which was optimized using an automated process based on a genetic algorithm, in order to maximize the quality factor. Optical characterization of several individual cavity replicas resulted in an average unloaded quality factor Q = 16,900 at the resonant wavelength {\lambda} $\sim 1.3$ {\mu}m, with a maximal measured Q value of 22,500. The statistics of both the quality factor and the resonant wavelength are well explained by first-principles simulations including fabrication disorder and background optical absorption.