Ferroelastic crystals as effective acoustooptic materials

Abstract

In this paper we analyse acoustooptic properties of ferroelastic crystals. It is shown that proper ferroelastics are the most attractive materials for utilisation in acoustooptic devices, due to low velocities of acoustic waves caused by anomalous behaviour of elastic properties in the vicinity of phase transition. A number of new ferroelastic compounds promising for acoustooptic applications are described.

Piezooptic coefficients and acoustooptic efficiency of TGS crystals

“…This value is much smaller than that typical for the best AO materials such as paratellurite [25], HgCl 2 [26] and Sn 2 P 2 S 6 [27] crystals, or some chalcogenide and ferroelastic crystals (see Refs. [28,29]). However, the above AO figure of merit is still comparable or even higher than the corresponding parameters of the other crystals transparent in the ultraviolet spectral region, e.g.…”

The anisotropy of acoustooptic figure of merit for the collinear diffraction in LiNbO3 crystals

“…Of course, this AOFM value is not so high if compared with the best AO materials (see, e.g., Refs. [19,20]). Nonetheless, for the case of collinear interaction this AOFM can lead to a 100% efficiency at the interaction lengths 10 -1 m, A= 25 mm 2 ,  = 632.8 nm and the AW powers as small as 5  10 -2 W.…”

Acoustic anisotropy of AgGaGe3Se8 crystals and their acoustooptic applications

“…As far as we know, the elastooptic coefficients and the AW velocities for AgGaGe 3 Se 8 have not yet been determined, although those parameters dominate the AOFM of the AO materials [23]. Below we present the first relevant results associated with the AW anisotropy for the AgGaGe 3 Se 8 crystals.…”

“…The AW velocities were measured with a pulse-echo overlap technique [24]. We exited the AWs in the samples using C , 12 C , 13 C , and 23 C . These coefficients have been calculated following from the known AW velocities and the relations 2 2 2 2 2 2 11 11 22 22 33 33 44 23 55 13 66 12 2 2 2 12 66 11 22 66 11 22 66 2 2 2 13 55 11 33 55 11 33 55 2 2 2 23 44 33 22 44 22 33 44 , , , , , , …”