Abstract

Terahertz quantum cascade lasers (QCLs) based on metal-metal waveguides have by far outperformed semi-insulating waveguides by operating at higher temperatures and lasing at low threshold current densities. Despite of the superior performance, metal-metal waveguide based THz QCL suffers from poor beam quality often due to high reflectivity of the mode and also due to multi-mode lasing which produce highly divergent beam profiles with multiple lobes. Such effects may have detrimental consequences for some applications. This aim of this paper is to introduce waveguide structures that suppress generation of higher order lateral modes in THz QCLs based on metal-metal waveguides.

© 2012 Optical Society of America