Mid-IR type-II interband cascade lasers and their applications

Type-II interband cascade lasers are efficient and compact mid-infrared. (3-5 mu m) light sources with many applications such as gas sensing and environmental monitoring. Significant progress toward such a goal has recently been made in terms of achieving low threshold current densities (e.g. similar to 8 A/cm(2) at 80 K), high temperature operation (e.g. 325 K in pulsed and 217 K in cw modes), and continuous wave operation of single-mode distributed feedback (DFB) lasers. These DFB lasers have been integrated into laboratory spectrometers for detection of gases such as CH4 and HCl. One laser was flown on a high-altitude balloon instrument and measured HCl profiles in the stratosphere as part of Aura satellite instrument validation. We review the recent progress of Sb-based mid-IR IC lasers and address the requirements for further improvements in their performance.