Lattice disorder, facet heating and catastrophic optical mirror damage of AlGaAs quantum well lasers

Abstract

Raman microprobe spectra from dry-etched, coated (110) AlGaAs single quantum well laser mirrors show, apart from the allowed phonon modes, a series of symmetry forbidden modes whose strength is dependent on the mirror treatment prior to coating. A particularly strong mode at 193 cm-1 can be attributed to disorder activated longitudinal acoustic phonon scattering in addition to - and this is new - the Eg-mode of elemental arsenic. The existence of lattice disorder and arsenic clusters is confirmed by Rayleigh scattering and energy dispersive x-ray spectroscopy. The optical power level at catastrophic optical mirror damage and the local mirror temperatures of the biased laser are found to have a strong dependence on mirror disorder.