A GaN photonic crystal membrane laser

Abstract

The implementation of a series of optically pumped GaN photonic crystal (PhC)membrane lasers is demonstrated at room temperature. The photonic crystal iscomposed of a scalene-triangular arrangement of circular holes in GaN. Threedefect structures are fabricated for comparing their lasing characteristics withthose of perfect PhC. It is observed that all the lasing defect modes have lasingwavelengths very close to the band-edge modes in the perfect PhC structure.Although those lasing modes, including band-edge and defect modes, have differentoptical pump thresholds, different lasing spectral widths, different quality factors (Q factors), and different polarization ratios, all their polarization distributions show maximain the directions around one of the hole arrangement axes. The similar lasingcharacteristics between the band-edge and defect modes are attributed to theexistence of extremely narrow partial band gaps for forming the defect modes.Also, the oriented polarization properties are due to the scalene-triangle PhCstructure. In one of the defect lasing modes, the lasing threshold is as low as0.82 mJ cm − 2, thecavity Q factor is as large as 1743, and the polarization ratio is as large as 25.4. Such outputparameters represent generally superior lasing behaviors when compared with previouslyreported implementations of similar laser structures.