Mid-infrared quantum cascade lasers combs for spectroscopy

The quantum cascade laser (QCL) has demonstrated operation over an extremely wide wavelength range extending from the mid-infrared at 2.9μm to the Terahertz at 360μm. In addition, quantum cascade lasers operating in the mid-infrared have now demonstrated extremely high powers with increasingly high wallplug efficiencies. In a new development, ultra low dissipation devices have been fabricated, operating with powers below 1W at room temperature. In particular, there is continuous interest in using External Cavity-Quantum Cascade Lasers (ECQCLs) for trace gas analysis because EC-QCLs offer a broad tuning range and are continuously tunable. The tuning speed is in principle only limited by the achievable grating rotation of the EC-QCL. Another advantage is the possibility to tailor the wavelength of the gain chip using quantum engineering..