MEMORY EFFECT FOR POLARIZATION OF PUMP LIGHT IN OPTICALLY PUMPED VERTICAL-CAVITY SEMICONDUCTOR-LASERS

We report that the polarization of the emission of an optically pumped vertical-cavity surface-emitting laser (VCSEL) is sensitive to the po larization state of the pump light. By measuring this memory effect fo r circularly polarized pump light, we determine the normalized relaxat ion rate of the carrier spin, Gamma(s), which is a vital parameter in current theoretical models of VCSEL polarization. We find Gamma(s) = 3 00+/-150, a value which is significantly larger than previously estima ted. We also observe a memory effect for the orientation of linearly p olarized pump Light. This signals that, apart from the carrier spin, t he VCSEL polarization is also determined by the carrier momentum.