Photoindiced laser scattering (PILS) and conoscopic patterns of LiNbO3:Gd and LiNbO3:Cu:Gd single crystals
Lithium niobate (LN) single crystals were grown by Czochralski at air from platinum crucibles at facility Crystal-2 (Zavod Kristall Ltd, Russian Federation). There were 2 double-doped crystals LiNbO3:Gd,Cu, sample 1 ([Cu]=0.57, [Gd]=0.07 wt%), sample 2 ([Cu]=0.041, [Gd]=0.076 wt%) and 4 single-doped crystals LiNbO3:Gd, sample 3 ([Gd]=0.003 wt%), sample 4 ([Gd]=0.01 wt%), sample 5 ([Gd]=0.05 wt%) and sample 6 ([Gd]=0.26 wt%). PILS and conoscopic patterns were studied using samples cut from LiNbO3:Cu:Gd and LiNbO3:Gd crystals in the shape of rectangular parallelepipeds 5×7×9 mm3. The longest side of each sample was cut along the X axis, parallelepipeds edges coincided with main crystal-physical axes X, Y, Z. Samples faces were thoroughly polished. A Nd:YAG laser MLL-100 (Changchun New Industries Optoelectronics, China) (λ = 532 nm, I up to ~ 6.29 W/cm2) was used in experiments on PILS and laser conoscopy. Radiation scattered by the crystal hit translucent screen and was registered by a digital video camera.