17,000 %/W Second Harmonic Conversion Efficiency in Single Crystalline Aluminum Nitride Microresonators

TL;DR

This paper reports a groundbreaking second-harmonic generation efficiency of 17,000%/W in single crystalline aluminum nitride microresonators, demonstrating a highly efficient integrated nonlinear optical platform.

Contribution

It introduces an optimized fabrication method for dually-resonant aluminum nitride ring resonators achieving record SHG efficiency and low power operation.

Findings

Achieved 17,000%/W second-harmonic generation efficiency.

Observed pump depletion at 3.5 mW input power.

Established epitaxial aluminum nitride as the highest efficiency SHG platform.

Abstract

High quality factor optical microcavities have been employed in a variety of material systems to enhance nonlinear optical interactions. While single-crystalline aluminum nitride microresonators have recently emerged as a low loss platform for integrated nonlinear optics such as four wave mixing and Raman lasing, few studies have investigated this material for second-harmonic generation. In this Letter, we demonstrate an optimized fabrication of dually-resonant phase-matched ring resonators from epitaxial aluminum nitride thin films. An unprecendented second-harmonic generation efficiency of 17,000%/W is obtained in the low power regime and pump depletion is observed at a relatively low input power of 3.5 mW. This poses epitaxial aluminum nitride as the highest efficiency second-harmonic generator among current integrated platforms.