Piezo-optic and elasto-optic effects in ammonium fluoroberylate crystals

All independent piezo-optic coefficients pi(im) of ammonium fluoroberylate (NH4)(2)BeF4 crystal are determined using the interferometric method. All independent elasto-optic coefficients p(ik) are calculated on the basis of pi(im) and elastic stiffness coefficients C-mk. Great attention is paid to the reliability of the pi(im) values. Several pi(im) coefficients have atypically large values (similar to 10-13 Br). An analysis of the spatial anisotropy of piezo-optic and elasto-optic effects was carried out on the basis of the indicative surfaces. The coefficients of acousto-optic figure of merit M-2 were determined for several geometries of acousto-optic interaction. The largest M-2 coefficients correspond to p(23) and p(33) coefficients and are 12.2 & sdot;10(-15) s(3)/kg and 10.7 & sdot;10(-15) s(3)/kg.