Coherence and focusing properties of unstable resonator semiconductor lasers

Abstract

The emission characteristics of unstable resonator semiconductor lasers were measured. The output of an 80-μm-wide laser consists of a diverging beam with a virtual source 5 μm wide located 50 μm behind the laser facet. A high degree of spatial coherence of the laser output was measured, indicating single lateral mode operation for currents I≲3 Ith.