Influence of adhesion layers on optical losses in THz quantum cascade lasers

Abstract

For a GaAs/AlGaAs terahertz (THz) quantum cascade laser (QCL) with a double metal waveguide (DMWG) based on Au and Cu metal plates and Ti and Ta adhesion layers, the dumping parameters and THz mode loss spectra were calculated. It has been shown that to minimize losses in high-temperature DMWG QCL designs, it is advisable to use Ti less than 5 nm thick or Ta less than 10 nm thick as adhesion layers for Au. The use of the proposed waveguide with a thickness of 20 µm will lead to the creation of a room temperature THz QCL.