Natural Optical Activity of AgGaSe₂

Abstract

A method for measuring the optical rotatory power in crystals which have both birefringence and optical activity effect is proposed. The rotatory power of AgGaSe 2 is measured by this method. It is found that the optical rotatory power in the [100] direction sharply decreases from 237°/mm to 40°/mm with increase in wavelength, from 750 nm to 950 nm, at room temperature. AgGaSe 2 is found to be optically isotropic at a wavelength of 811 nm, the rotatory power at this wavelength being 118°/mm.