Mid-infrared quantum cascade lasers and applications

Quantum Cascade (QC) lasers are a rapidly evolving mid-infrared and THz, semiconductor laser technology based on intersubband transitions in multiple coupled quantum wells. The lasers´ strengths are their wavelength tailorability, high performance and fascinating design potential. The authors will first give a brief introduction into QC lasers followed by a discussion of several recent highlights, such as the quest for high performance QC lasers, especially high efficiency and single-mode operation, and the implementation of unconventional laser schemes. The authors will also discuss several applications, predominantly trace gas sensing applications.