Deflection of Light by Ferroelectric-Ferroelastic RbHSeO4

Properties of the light deflection due to domains in ferroelectric-ferroelastic RbHSeO 4 have been examined. Above a critical angle of incidence, five deflected beams are observed with a He–Ne laser incidence for both a -cut and b -cut plates of RbHSeO 4 . Below the critical angle, only two deflected beams appear and the deflection angles at the incident angle of 0° are ±24.3° and ±15.8° for the a -cut and b -cut plates, respectively. The critical angles are equal to the angles of deflection at the incident angle of 0°. The intensity of the deflected beams extends from 1% to 15% of that of the incident one. The incident angle dependence of the deflection one and the polarizing directions of the deflected beams are explained qualitatively on the basis of crystal optics.