ABSTRACT
In this chapter, the authors discuss some spontaneous emission characteristics in microcavity surface emitting lasers (SELs). Modified distribution of modes in the SEL is calculated and displayed over the optical wave vector space (k-space). The spontaneous emission factor is calculated to evaluate the amount of spontaneous emission control in the SELs and the possibility of the thresholdless operation. The spontaneous emission factor for the Bragg resonant mode in microcavity SELs is as large as 103 to 105 times that in conventional horizontal cavities. It is not so dependent on the vertical cavity quality but is almost inversely proportional to the cavity lateral size. To realize such an SEL experimentally, the reduction of the nonradiative recombination at the microcavity surface will be the important issue. In addition, investigation of the absolutely closed cavity structure will provide more remarkable effects of the microcavities.
