A vertical-cavity surface-emitting laser (“VCSEL”) has at least a substrate, electrical contacts, a first mirror region, a second mirror region and an active region between the mirror regions; where the mirror regions comprise distributed Bragg reflectors formed of a plurality of layers; laser emission is from at least one gallium arsenide antimonide nanostructure in the active region; and each said nanostructure contains more antimony atoms than arsenic atoms.