NONCOLLINEAR ACOUSTOOPTIC TUNABLE FILTER - THALLIUM PHOSPHORUS SELENIDE SYSTEM

Single crystals of thallium phosphorous selenide Tl3PSe4, were grown from the melt by the Bridgman method. The crystal quality was evaluated by optical and metallographic techniques. The crystals transmit radiation between 0.7 and 14 mum. Etchpit studies show that the crystals are free from inclusions and lamellar twins and exhibit a uniform cross-sectional etchpit density. Thallium phosphorous selenide crystals are biaxial and belong to the orthorhombic crystal class. A detailed design for the noncollinear acousto-optic tunable filter that uses Tl3PSe4 crystal is presented. Design of filters from this class of crystals facilitates control of the angular aperture, an important device parameter.