1LO-phonon assisted injection observed in a THz Quantum Cascade Laser

Abstract—We report on the observance of a GaAs/AlGaAs based Quantum Cascade Laser with no injector/extractor region which lases while utilizing LO-phonon assisted injection. With the magnetic field parallel to the grown axis, the voltage versus current and magnetic field both show a sharp change, corre-sponding to an energy of an LO-phonon, while still lasing. This shift of voltage above the normal lasing condition is attributed to the QCL transitioning from a resonant tunneling injection to an LO-phonon assisted injection regime. I