Visualization of the Effect of an Impurity on the Optical Homogeneity of Lithium Niobate Doped with Boron Cations

The laser conoscopy method confirms the high optical uniformity of LiNbO3:B crystals in the range of B2O3 concentrations from 0.008 to 1.24 mol. %. Minor signs of anomalous optical biaxiality appear in the conoscopic patterns of crystals at boron concentrations of 0.12 and 0.83 mol. % at a laser power of 90 mW. The maximum value of the angle of anomalous optical axes for the studied samples is 2V = 10 ́ for the sample (0.12 mol. %), аnd the value of anomalous birefringence corresponds to ∆n = 0.02·10-5.

Control of Optical Homogeneity of Lithium Niobate Crystals with Admixtures of Rare-Earth Elements Gd, Er by Laser Conoscopy

Interference patterns of single crystals of LiNbO3:Gd, LiNbO3:Er, obtained by laser conoscopy, allow us to estimate the optical homogeneity of the samples under study. The observation of conoscopic patterns of the LiNbO3:Gd single crystal shows that with an increase in the percentage impurity concentration, the anomalous biaxiality in these samples manifests itself to a much greater degree. Anomalous biaxiality for the sample LiNbO3:Er [3.60 wt.%] is present at almost every point of the entrance face, which is manifested in conoscopic patterns in the form of enlightenment and rupture of the “Maltese cross”, which corresponds to the angle 2V~1° between the anomalous axes.

Controllable and directional growth of Er:Lu2O3 single crystals by the edge-defined film-fed technique

The sesquioxide Lu2O3 single crystal, with high quality and optical homogeneity, has been grown controllably with an oriented seed by EFG method for the first time. The EFG method is promoted to an extremely high temperature of 2450 °C.

Noncontact Control by Laser Conoscopy of Optical Homogeneity of Heavily Doped LiNbO3: Zn

A non-contact method using laser conoscope the studies of optical homogeneity of a series of heavily doped LiNbO3crystals (4.46–4.69 mol. % ZnO). For all crystals not detected additional anomalies in сonoscopic patterns at increase of laser radiation power up to 90 mW, due to the presence of static and fluctuating defects induced in the photorefractive crystal by laser radiation.