Cleaved cavity optically pumped InGaN–GaN laser grown on spinel substrates

Abstract

We report an optically pumped multiple-quantum-well laser of InGaN–GaN grown on cubic, (111)-oriented spinel substrates. The laser cavity is formed by cleaving. Atomic force microscopy shows that the cleaved GaN and spinel facets are of similar flatness. The onset of lasing is clearly demonstrated by the saturation of spontaneous emission, abrupt line narrowing, and the highly polarized light output. A lasing threshold power of 140 kW/cm2 is measured in a 400-μm-long cavity at 150 K.