The indicative surfaces of the photoelastic effect in Cs2HgCl4 biaxial crystals

We present a new method to calculate the indicative surfaces of the photoelastic effect in biaxial crystals. The corresponding equations are derived and applied to the calculations of the indicative surfaces of the longitudinal and transverse photoelastic effects in orthorhombic Cs2HgCl4 crystals. By means of the indicative surfaces the spatial anisotropy of photoelastic interaction in Cs2HgCl4 crystals is evaluated.