Long wavelength (λ = 10 - 20 µm) mid-IR quantum cascade lasers for spectroscopy applications

We report new developments of quantum cascade lasers (QCL), made of InAs/AlSb, operating in the long wavelength mid-infrared range from 10 to 20 µm. Fabry-Perot lasers operated in the CW regime up to a wavelength of 18 µm at 40°C, and up to 21 µm on Peltier cooler, with threshold current densities below 1 kA/cm². Distributed feedback QCL are also fabricated using a metal grating on the top of the laser ridges. They demonstrated single frequency operation in CW regime at room temperature. These lasers are suitable for new high resolution spectroscopy applications in this almost unexplored spectral range.