Laser rods characterization by Fourier transform phase-shifting interferometry

Abstract

Solid-state lasers are broadly used in various applications. The most common gain medium is neodymium-doped yttrium aluminum garnet (Nd:YAG). Very important parameters are angle between polished face surfaces and result wave-front deformation. These parameters are usually measured with two different methods. The paper presents a procedure for measurements of the parameters in a single measurement sequence using Fourier transform phase-shifting interferometry. The results are figures of both optical surfaces, and their mutual position, wave-front deformation, and homogeneity of refractive index. Based on the knowledge of these parameters can be done precise correction of resulted wave-front and of the wedge by polishing of face surfaces. The presented method reduces manipulation with the elements is non-sensitive to the operator and allows more precise wavefront correction thanks to the knowledge of inhomogeneity of material.