GaN Surface-Emitting Laser With Monolithic Cavity-Folding Mirrors

We report on the demonstration of a GaN-based surface-emitting laser (SEL) in a folded-cavity (FC) scheme. Two 45deg-angled sidewall deflectors were monolithically integrated at both the edges of an otherwise conventional InGaN multiple-quantum-well edge-emitting laser structure. Despite a low effective mirror reflectivity of R(<1%), the optically pumped broad-area laser structure produced laser oscillation in the vertical direction with a low threshold pump intensity of ~350kW/cm². Computer simulations on the FC, which was based on the finite-difference time-domain method, not only quantified the cavity quality of our FC-SEL device but also suggested methods to lower the laser threshold