Demonstration of polarization control GaN-based micro-cavity lasers using a rigid high-contrast grating reflector.

Sci Rep

Department of Photonics, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan.

Published: September 2019

We reported on GaN microcavity (MC) lasers combined with one rigid TiO high-contrast grating (HCG) structure as the output mirror. The HCG structure was directly fabricated on the GaN structure without an airgap. The entire MC structure comprised a bottom dielectric distributed Bragg reflector; a GaN cavity; and a top HCG reflector, which was designed to yield high reflectance for transverse magnetic (TM)- or transverse electric (TE)-polarized light. The MC device revealed an operation threshold of approximately 0.79 MW/cm when pulsed optical pumping was conducted using the HCG structure at room temperature. The laser emission was TM polarized with a degree of polarization of 99.2% and had a small divergence angle of 14° (full width at half maximum). This laser operation demonstration for the GaN-based MC structure employing an HCG exhibited the advantages of HCGs in semiconductor lasers at wavelengths from green to ultraviolet.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6736857PMC
http://dx.doi.org/10.1038/s41598-019-49604-0DOI Listing

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