Study of the optical rotation of potassium titanyl phosphate using the advanced dual-wavelength polarimetric method

Abstract

An advanced dual-wavelength high-accuracy universal polarimeter was applied to measure optical activity in potassium titanyl phosphate (KTP) nonlinear crystal. Two single-mode He-Ne lasers with close wavelengths of 594 and 633 nm were used as light sources in the experimental setup. Multiple internal reflection of the light was taken into account when processing the results of the polarimetric measurements. Analysis of the optical transmission function for the polarizer-sample-analyzer system and 2D intensity contour maps made it possible to determine the phase parameters, systematic errors, and eigenwaves ellipticity. Gyration tensor component of the KTP crystal is equal to g₁₂ =1.4 · 10^-5 which in terms of optical rotatory power corresponds to the value of 2.3 deg/mm.