Nonlinear optical properties of CdI/sub 2/ single crystals, doped with 3D-metals iodides

Abstract

Wide band gap layered single crystals CdI/sub 2/ (4H) have close-packed hexagonal lattice. Doped with CuI and NiI/sub 2/ crystals for investigations were grown from the melt by the Bridgman method. The layered crystals possess surfaces of high quality (mirror-like quality), which are parallel to the layers. Doping improves nonlinear properties of crystals CdI/sub 2/; in particular increases the efficiency of generation of the second harmonic (SHG). SHG temperature dependencies in NiI/sub 2/ and CuI-doped crystals are investigated. All studied samples were pre-treated in magnetic fields at 4.2 K for 4 hrs. SHG signal decreases with temperature. Thus the ordering in impurity atom location is accompanied by the appearance of polarization charges on crystals surface and by increased lattice eccentricity.