Optomechanical zipper cavity lasers: theoretical analysis of tuning range and stability

TL;DR

This paper presents a theoretical and experimental study of zipper cavity lasers, demonstrating high wavelength tunability up to 75nm, analysis of thermal noise effects, and stabilization techniques using radiation pressure, with fabrication in GaAs with quantum dots.

Contribution

It introduces a novel zipper cavity laser design with large tunability and analyzes stabilization methods against thermal noise, including fabrication and experimental validation.

Findings

Achieved tuning ranges up to 75nm at 1.3 microns.

Identified radiation pressure as a means to stabilize laser frequency.

Fabricated zipper cavity lasers with embedded quantum dots in GaAs.

Abstract

The design of highly wavelength tunable semiconductor laser structures is presented. The system is based on a one dimensional photonic crystal cavity consisting of two patterned, doubly-clamped nanobeams, otherwise known as a "zipper" cavity. Zipper cavities are highly dispersive with respect to the gap between nanobeams in which extremely strong radiation pressure forces exist. Schemes for controlling the zipper cavity wavelength both optically and electrically are presented. Tuning ranges as high as 75nm are achieved for a nominal design wavelength of 1.3micron. Sensitivity of the mechanically compliant laser structure to thermal noise is considered, and it is found that dynamic back-action of radiation pressure in the form of an optical or electrical spring can be used to stabilize the laser frequency. Fabrication of zipper cavity laser structures in GaAs material with embedded self-assembled InAs quantum dots is presented, along with measurements of photoluminescence spectroscopy of the zipper cavity modes.