Optical rotatory power of nonlinear potassium titanyl arsenate crystals measured using improved dual-wavelength polarimetry

An improved dual-wavelength high-accuracy polarimetric method was used to investigate the optical rotatory power (ORP) of potassium titanyl arsenate (KTiOAsO 4 , KTA) crystals. Two He–Ne lasers with identical beam properties, operating at closely spaced wavelengths of 594 and 633 nm, were used for the measurement. The magnitude of the gyration tensor component is g 12 = 4.40(21) × 10 −5 , which corresponds to an ORP of ρ = 6.40 (31)° mm −1 , more than three times lower than the previously reported value. Calculations of the systematic error parameters from polarimetric studies for two directions of light propagation show that these KTA crystals exhibit high optical quality.