Quantum cascade laser (QCL) in airborne atmospheric measurements: a review [Invited]

The invention of QCL raised great expectations among atmospheric physicists, because of its emission in the mid-infrared, compared to laser diodes, and its optical power and spectral purity, with respect to lead salt lasers. Nowadays in the middle infrared, QCLs are the pillars for any application in which high sensitivity is a must (less demanding applications can be carried out by laser diodes). This review reports on the history of the introduction of QCLs in atmospheric measurements, shows significant applications to aerial platforms, and describes their outlook.