Low-loss wavelength tuning of a mid-infrared Cr2+:ZnSe laser using a Littrow-mounted resonant diffraction grating

Abstract

We report the first demonstration of resonant-grating-based laser wavelength tuning in the mid-infrared spectral domain and with Littrow mounting of the grating. We show for a mid-infrared Cr:ZnSe laser that this tuning technique is much more wavelength selective than prism-based tuning, while inducing very low cavity losses (around 2%), which are at least two times smaller than in the case of a standard metal grating. Furthermore, the resonant grating allows tuning the Cr:ZnSe laser over as much as 400 nm around a center wavelength of 2.38 μm. This shows the potential of employing Littrow-mounted resonant diffraction gratings for controlling and tuning the emission wavelength of lasers emitting in the mid-infrared spectral domain and other wavelength regions.