Single-Frequency Broadly Tunable Cr:ZnSe Laser

Single-frequency lasers have fundamental impact in a broad variety of applications, like high-resolution spectroscopy and LIDAR applications due to their low intensity and phase noise. Moreover, in the mid-infrared spectral region, broadband tunable single-frequency lasers stand out as simple, robust and cost-effective sources to perform precision absorption spectroscopy of fundamental absorption spectra of organic and inorganic molecules. To this aim, the broad emission of a tunable CrZnSe laser around 2.4 μm is of particular interest due to the spectral coincidence with fundamental electric dipole and electric quadrupole absorption spectrum of the HD hydrogen isotopologue in the range from 3360 to 4360 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> (corresponding to 2.976 to 2.294 μm) [1].