The performance of mid-IR interband cascade lasers (ICLs) has been improved by introducing heavier doping into
the electron injector regions with the purpose of increasing the electron density in the active region to the level
commensurate with the active hole density. For devices emitting at wavelengths in the 3.6-3.9 μm range, the
improvements include pulsed room temperature (RT) threshold current density as low as 170 A/cm2, maximum cw
operating temperature as high as 109 °C, and RT cw input power as low as 29 mW. Epi-down-mounted ridges
display RT cw wall-plug efficiencies as high as 14.6% as well as emission of > 200 mW into a nearly diffraction-limited
beam. RT cw operation has also been demonstrated for considerably longer wavelengths extending to 5.7
μm with threshold power densities of ≈1kW/cm2, which are an order of magnitude lower than those in state-of-theart
quantum cascade lasers. The very low operating powers are expected to lengthen battery lifetimes and greatly
relax packaging and size/weight requirements for fielded chemical-sensing systems.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
W. W. Bewley ; C. D. Merritt ; C. S. Kim ; M. Kim ; C. L. Canedy, et al.
"Mid-IR interband cascade lasers operating with < 30 mW of input power", Proc. SPIE 8374, Next-Generation Spectroscopic Technologies V, 83740H (May 1, 2012); doi:10.1117/12.918572; http://dx.doi.org/10.1117/12.918572