Light diffraction with conservation of optical mode by slow shear acoustic wave in paratellurite

摘要

Abstract: This paper is devoted to analysis of acousto-optic Bragg diffraction in tellurium dioxide single crystal in case of bulk slow shear ultrasonic waves propagating in the material. The so-called 'isotropic' type of the diffraction by the acoustic wave is examined in the paper. Contrary to the well known 'isotropic' diffraction, the investigated acousto-optic interaction is characterized by conservation of initial optical mode int he crystal. It is proved that the discovered regime of isotropic interaction in an anisotropic material is similar to interaction in optically isotropic media. The paper acquaints with equation representing dependencies of Bragg incidence angles on acoustic frequency in the crystal. The derived equations are different from the known equations in isotropic media. Experimental results on measurements of frequency dependencies of Bragg incidences angles in paratellurite are presented in the paper. Peculiar dependencies of diffraction efficiency on amplitudes of acoustic waves are also discussed in this paper. Peculiar dependencies of diffraction efficiency of the examined isotropic interaction may be higher than the efficiency of the anisotropic scattering. As proved experimentally, maximum diffraction efficiency values for the investigated isotropic diffraction in tellurium dioxide may exceed 60 percent. !10