Piezo-, elasto- and acousto-optic properties of Tl 3 AsS 4 crystals

Complete matrices of piezo-optic and elasto-optic tensors are experimentally determined for Tl AsS crystals. It is revealed that the piezo-optic coefficients are very high, ∼10 N/m in the order of magnitude. This implies that Tl AsS can be referred to the best piezo-optic materials. The same concerns the elasto-optic coefficients, of which absolute values are in the interval 0.28-0.54. It is also found that, at the anisotropic and isotropic interactions with the slowest transverse and longitudinal acoustic waves, the acousto-optic figure of merit reaches extremely high values (1.99×10 s /kg and 9.45×10 s /kg, respectively). In other words, the Tl AsS crystals can be referred to as one of the best acousto-optic materials for the visible and infrared spectral ranges.