Piezo-, elasto- and acousto-optic properties of Tl₃AsS₄ crystals

Abstract

Complete matrices of piezo-optic and elasto-optic tensors are experimentally determined for TlAsS crystals. It is revealed that the piezo-optic coefficients are very high, ∼10 N/m in the order of magnitude. This implies that TlAsS 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 TlAsS crystals can be referred to as one of the best acousto-optic materials for the visible and infrared spectral ranges.

Acoustooptic figure of merit of Tl3AsS4 crystals. The case of acoustic waves propagation along crystallographic axes

“…These parameters are respectively equal to p 31  0.27, p 32  0.32 and p 33  0.39 (at 632.8 nm   ), and determined under the conditions of isotropic interactions of the optical waves polarized along the crystallographic axis c with the longitudinal acoustic waves propagating along the crystallographic axes. It would be worthwhile to remind in this respect that the velocity of the quasi-longitudinal wave does not manifest essential anisotropy, varying from 2077 to 2369 m/s [7]. On the other hand, the so-called principal EOCs lie in the region 0.28-0.54 and so can change almost twice.…”

“…Moreover, Tl 3 AsS 4 is a promising material for thermal imaging [6]. Recently, we have determined the complete matrices of piezooptic and elastooptic coefficients (EOCs) [7] for the Tl 3 AsS 4 crystals, together with the complete matrices of elastic stiffness and compliance coefficients [8]. It has been found that the piezooptic coefficients are very high, being 10 -11 N/m 2 in the order of magnitude.…”