Vertical cavity surface emitting laser, transverse energy emission in gain medium used to augment laser output

摘要

A vertical cavity surface emitting laser (VCEL) has a semiconductor gain medium 22. Energy source such as electrode 40 energises the gain medium in a first volume 40. This causes spontaneous and stimulated emission to propagate in the gain medium in a direction 48 transverse to the fundamental cavity mode. The transverse emission pumps the gain medium in a second volume surrounding the first. The emission from the second volume is coupled into the fundamental cavity mode and adds to the emission coupled form the first volume, this utilises otherwise wasted transverse emission.