Conoscopic Studies of Optical Homogeneity of the LiNbO3:Mg Crystals

An essential modification of the method to observe large-scale conoscopic images is proposed. Divergent beam of wide-aperture radiation is formed by a diffuser placed before entrance of a lithium niobate crystal. The optical homogeneity of LiNbO3:Mg crystals is studied in a wide range of the admixture concentrations (0.01 – 5.5 mol.%). An inhomogeneous distribution of the admixture is found to increase with the admixture concentration being accompanied by growth bands, micro-defects, such as micro-domains, domain boundaries, and block structures particularly in parts of higher concentration gradients at the boundaries of the growth bands.