Two-phonon-resonance terahertz quantum cascade laser based on GaN/AlGaN material system

In this paper, a two-phonon-resonance terahertz quantum cascade laser (THz QCL) based on GaN/AlGaN material system is proposed. GaN/AlGaN material system is first studied in two-phonon-resonance active region structure by using rate equations. The active region adds an energy state above the upper laser state. The energy state difference between additional state and the upper laser state is equal to the longitudinal optical phonon energy which has a large magnitude (similar to 90 meV). The simulation results show that the proposed THz QCL can get better optical properties compared with the traditional three-level active region building in the same material system and has the superiority in improving electronic utilization. The results also show that two-phonon-resonance THz QCL based on GaN/AlGaN material system can gain the peak output power of 8 mW at the temperature of 230 K.