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

• Published in: Scientific reports Vol. 9; no. 1; pp. 13055 - 6
• Main Authors: Chang, Tsu-Chi, Hong, Kuo-Bin, Kuo, Shuo-Yi, Lu, Tien-Chang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.09.2019; Nature Publishing Group
• Subjects: 140/125; 142/126; 639/624/1020/1093; 639/624/399/1097; Humanities and Social Sciences; Lasers; multidisciplinary; Polarization; Polarized light; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-49604-0

We reported on GaN microcavity (MC) lasers combined with one rigid TiO 2 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 2 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.