Gain Structure for Spin Lasers

Abstract

This project focusses generally on gain structures for spin lasers that recently considered a hot research area in the spintronic field due to its promising applications and advantages. However, this article first provides a background about the semiconductor lasers then reviewing the gain structures of spin lasers, especially on the vertical-external cavity surface-emitting laser (VECSEL) that based on quantum dots. The article investigating the possibility of spin memory in optically pumped InAs quantum dot (QD) sandwiched by In_0.12 Ga_0.88 As quantum well (QW) by investigating the polarization properties of photoluminescence (PL) through Stokes parameters. It is important to indicate that the data of this experiment was taken by a previous student and it has been reanalysed by the writer. It has been found that change of input helicity gave a change of output helicity which is indicating to spin memory. However, for a linear pump also a small output helicity was found which is indicating a systematic error. Nevertheless, this gives the first evidence of spin memory phenomena by using QD-VECSEL.