PHYSICS OF SEMICONDUCTOR VERTICAL-CAVITY SURFACE-EMITTING LASERS

We describe recent progress in the physics of light-matter interaction s in vertical-cavity surface-emitting-laser (VCSEL) structures. Enhanc ed spontaneous emission indicates strong medium-cavity coupling. The l inewidth broadening factor is more accurately determined in VCSELs, su pporting many-body theory of semiconductor nonlinearities. Threshold b ehavior of VCSELs and microlasers is investigated by photon-correlatio n experiment and quantum laser theory with emphasis on the importance of second-order coherence properties. External optical injection into a VCSEL cavity leads to injection locking, instabilities, acceleration of coherent energy transfer and sideband lasing, most of which are mo deled successfully by recently-developed first-principles semiconducto r laser theory.