Circularly symmetric operation of a concentric-circle-grating, surface- emitting, AlGaAs/GaAs quantum-well semiconductor laser

A surface-emitting semiconductor laser that utilizes a concentric-circle grating defined by electron-beam lithography is observed to oscillate in a circularly symmetric fashion. The laser emits a circularly symmetric beam with a total beam divergence of less than 1°. Despite its broad-area geometry, the laser shows no evidence of filamentation. The laser maintains a relatively narrow wavelength spectrum approximately 1 Å in width.