Phosphides-Based Terahertz Quantum-Cascade Laser

Due to their high optical phonon energies GaInP/AlGaInP heterostructures are a promising active medium to solve the problem of creating compact semiconductor sources with an operating frequency range of 5.5-7 THz. In this work, the temperature dependences of gain and absorption at 6.4-6.9 THz have been calculated for a GaInP/AlGaInP-based quantum-cascade laser (QCL) with two quantum wells in the cascade and a metal-metal waveguide. The dielectric function and mode losses for a 10 mu m thick Au-Au waveguide, based on ternary InGaP and quaternary AlGaInP semiconductors, have been investigated in details. A laser structure that provides a mode gain of over 100 cm-1 with a maximum operating temperature about 100 K is proposed. The results of this study open the way to the development of a QCL for operation in a significant part of the GaAs phonon absorption band region, which is inaccessible for existing QCLs. The GaInP/AlGaInP heterostructures have higher optical phonon energies compared to GaAs/AlGaAs heterostructures. We propose a scheme of phosphides-based terahertz quantum cascade laser. The proposed design has opportunity of operation in a significant part of the GaAs phonon absorption band region, which is inaccessible for existing quantum cascade lasers (QCLs).image (c) 2024 WILEY-VCH GmbH