Optical Guiding and Feedback Structures in GaN-Based Vertical-Cavity Surface-Emitting Lasers

Sammanfattning: The gallium-nitride (GaN) semiconductor material has been the core of the revolutionary breakthroughs during the last two decades in the lighting industry, by enabling manufacturing of efficient blue light emitting diodes (LEDs), for which the 2014 Nobel prize in physics was awarded. The GaN technology has further led to violet edge-emitting lasers (EELs), enabling the Blu-ray disk technology, and also to the commercialization of directly green emitting EELs. A natural next step is the realization of GaN-based vertical-cavity surface-emitting lasers (VCSELs), which has proved to be a challenging task. The first electrically injected GaN-based VCSEL was announced in 2008, more than a decade after the first reports on its EEL counterpart. Still today only a few groups in the world have demonstrated lasing under continuous-wave operation in a blue VCSEL.