Implementation of the wide-angle acousto-optical interaction geometry in a mercury bromide single crystal

A number of acousto-optic figures of merit and elasto-optic constants of a mercury bromide (Hg₂Br₂) crystal were measured. The key characteristics of the wide-angular acousto-optic tunable filter based on a Hg₂Br₂ crystal in the (11¯0) plane were calculated from the measurements carried out and previously known data. It is demonstrated that the crystal makes it possible to create effective devices operating in the 5-25 µm wavelength range. In addition, we proposed the design of a filter operating in the long-wavelength infrared range of 8-12 µm, providing spectral resolution up to R=300 and a field of view outside the crystal up to 10°. Its diffraction efficiency can reach up to 2% per 1 W of continuous driving power.