The mid-infrared region (MID-IR) is usually considered spanning from 3 to 8 μm wavelength. This is an extremely useful region for many applications because roto-vibrational transitions of molecules lie in this region. In fact, possible applications comprise material analysis, quality control, dynamic measurements, environmental and medical monitoring applications, forensic testing, analysis of art objects, etc. Historically, laser sources in this region were bulky and did not permit the development of wide-spread applications. The situation dramatically changed in the last decades with the advent of compact coherent sources like quantum cascade lasers, which, unfortunately, possess intrinsic limitations as for output peak power and beam quality.
