Control of Electron Spin Relaxation Dynamics and Circularly Polarized Lasing in Semiconductor Lasers

Abstract

We investigated spin-controlled semiconductor lasers which can emit circularly polarized coherent light by utilizing electron spin polarization and the optical selection rule. We fabricated a (110)-oriented vertical-cavity surface-emitting laser (VCSEL) with GaAs/AlGaAs quantum wells (QWs) and characterized lasing properties of the VCSEL under optical spin injection. Circularly polarized lasing with a high degree of circular polarization of 0.96 in the VCSEL was demonstrated at room temperature originating from a long electron spin relaxation time in the (110) GaAs QWs. We also demonstrated a tenfold modulation of electron spin relaxation time from 4 to 0.3 ns in the (110) GaAs QWs through the Rashba spin-orbit coupling induced by applying an external electric field at room temperature.