Photo-Assisted Wet-Etched III–V Heterostructure Laser Mirrors

We demonstrate the first photo-assisted wet-etched flat-surface mirrors in III-V laser heterostructure having an average reflectance of 0.87 of the ideal cleaved facet reflectance
R

_c
independent of crystal orientation. The largest observed reflectance was 0.93
R

_c
. These lasers were fabricated using a 532-nm laser source, sulfuric acid, and exposed-metal mask. The lateral waveguiding formed from air-semiconductor interfaces produced an average internal loss of 28/cm (smallest of 14/cm) compared with similar cleaved-mirror dark-etched lasers having 46/cm.