Phosphides-based terahertz quantum-cascade laser

Abstract

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 μm 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.