Design of a $ZnMnSe∕ZnMgSe$ spin-polarized terahertz quantum cascade laser tunable by magnetic field

A design of a magnetic field tunable $ZnMnSe∕ZnMgSe$ terahertz quantum cascade laser is proposed. It relies on the spin-dependent potential induced by a magnetic field. The electron dynamics are calculated using the Boltzmann equation approach, with electron-longitudinal optical phonon, electron-longitudinal acoustic phonon, and electron-electron scattering included. Tunability of the emission energy between 10 and $26meV$⁠, and 38 and $42meV$⁠, for transitions of spin-down and spin-up electrons, respectively, may be achieved by varying a magnetic field up to $5T$⁠, at a temperature of $1.5K$⁠. Population inversion of up to 42% for spin-down and 27% for spin-up electrons is predicted, which in conjunction with the estimated waveguide losses, yields sufficient gain for laser operation.