Abstract
Terahertz quantum cascade laser (THz-QCL) is a compact, high output power, narrow linewidth and low
cost terahertz laser, and is very attractive for a lot of applications as a practical use terahertz light source.
In this report, we demonstrate our recent research activities on the development of high performance
THz-QCLs, i.e., realization of higher temperature operation of THz-QCL using an indirect injection
scheme QC design, high output power operation of THz-QCLs at 77 K liquid nitrogen temperature and
development of unexplored frequency THz-QCLs using nitride semiconductors. Through these studies,
we also discuss on the future prospects of THz-QCLs.
