Current status and prospect of quantum cascade lasers

Abstract

After the first demonstration of GaInAs/AlInAs quantum cascade lasers (QCLs) by band-structure engineering and molecular beam epitaxy, QCLs have shown rapid and marked progress. Recently, QCLs have been drawing much attention because the room-temperature continuous wave operation of mid-infrared QCLs and the demonstration of THz QCLs have been realized. In this article, we describe the operation and design of QCLs and review these two topics.