Deflection of Light by Ferroelastic Domains in Gd₂(MoO₄)₃ and Bi₄Ti₃O₁₂ Crystals

Abstract

The relation between angles of incidence and deflection caused by the refraction and reflection of light beam at the ferroelastic domain walls in Gd₂(MoO₄)₃, Bi₄Ti₃O₁₂ and Rochelle salt crystals has been treated on the basis of crystal optics. Numerical analysis of the relation has been carried out for incident angles from 0° to 90°. At the incident angle of 0°, the deflection angles obtained by the analysis are 2.25° for the c plate of Gd₂(MoO₄)₃, 14.6° for the b plate of Bi₄Ti₃O₁₂ and 4.43° for the a plate of Rochelle salt. The experimental results with a He–Ne laser for these crystals are in satisfactory agreement with the calculated ones. The intensity ratio of the deflected beam to the direct beam is in the order of 10⁻² for Gd₂(MoO₄)₃ and 10⁻³ for Rochelle salt.