Circularly polarized lasing over wide wavelength range in spin-controlled (1 1 0) vertical-cavity surface-emitting laser

We investigated the emission wavelength dependence of the lasing polarization in a (1 1 0)-oriented vertical-cavity surface-emitting laser (VCSEL) with GaAs/AlGaAs quantum wells under optical spin injection at room temperature. Lasing was observed in the one circularly polarized mode over a wide wavelength range from 838 to 857 nm, in which a degree of circular polarization higher than 0.8 was maintained. The optical gain spectrum that contributed to the circularly polarized lasing is discussed based on the optical selection rules and the measured polarization-resolved photoluminescence spectra of the active layers.