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

2020 ◽  
Vol 992 ◽  
pp. 971-975
Author(s):  
O. Pikoul ◽  
Nikolay V. Sidorov ◽  
Mikhail N. Palatnikov
Keyword(s):  
Rare Earth ◽  
Lithium Niobate ◽  
Rare Earth Elements ◽  
Single Crystals ◽  
Impurity Concentration ◽  
Optical Homogeneity ◽  
Maltese Cross ◽  
Lithium Niobate Crystals ◽  
Laser Conoscopy ◽  
Entrance Face

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.

Visualization of Optical Uniformity Alloyed Single Crystals of Lithium Niobate

2020 ◽  
Vol 312 ◽  
pp. 140-147
Author(s):  
Olga Y. Pikoul ◽  
Nikolay V. Sidorov ◽  
Natalya A. Teplyakova ◽  
Mikhail N. Palatnikov
Keyword(s):  
Lithium Niobate ◽  
Single Crystals ◽  
Mechanical Stresses ◽  
Field Of View ◽  
Local Change ◽  
Defective Structure ◽  
Maltese Cross ◽  
Peripheral Area ◽  
Laser Conoscopy ◽  
Elastic Characteristics

It was shown that laser conoscopy can visually detect even slight changes in the optical characteristics of a crystal when it is doped. It has been found that the defective structure of LiNbO3:Zn (4.5 mol. %), LiNbO3:Mg (3.0–5.5 mol.%) crystals associated with an uneven entry of an impurity leads to a local change in the elastic characteristics of the crystal and the appearance of mechanical stresses that distort the conoscopic patterns. This can be an abnormal optical biaxiality, which manifests itself in the form of a rupture and enlightenment of the "Maltese cross" in the center of the conoscopic crystal pattern, or local birefringent inclusions that are recorded as additional interference patterns against the background of the main conoscopic pattern, both in the center of the field of view and in its peripheral area.

Investigation of optical homogeneity and photorefractive properties of lithium-niobate single crystals by the Raman-spectroscopy and laser-conoscopy methods

2013 ◽  
Vol 115 (4) ◽  
pp. 523-529 ◽  
Author(s):  
N. V. Sidorov ◽  
M. N. Palatnikov ◽  
A. A. Yanichev ◽  
A. A. Gabain ◽  
O. Yu. Pikoul ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Lithium Niobate ◽  
Single Crystals ◽  
Optical Homogeneity ◽  
Laser Conoscopy

scholarly journals X-RAY studies of ferroelectric lithium niobate crystals doped with rare earth elements

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 114-119
Author(s):  
A. V. Kadetova ◽  
◽  
M. N. Palatnikov ◽  
O. V. Sidorova ◽  
D. A. Vorobyov ◽  
...  
Keyword(s):  
Rare Earth ◽  
Lithium Niobate ◽  
Rare Earth Elements ◽  
Crystal Lattice ◽  
Polar Axis ◽  
X Ray Diffraction ◽  
Defect Region ◽  
X Ray ◽  
Structural Distortions ◽  
Lithium Niobate Crystals

The lattice structural distortions of LiNbO3 crystals doped with samarium with a concentration of 1.0, 1.9, 2.5 mol. % were studied by X-ray diffraction methods. It was found that the samarium atoms and some of the niobium atoms occupied the vacant positions of lithium in the crystal lattice, and some of the niobium atoms were located in the empty octahedron. The octahedra of SmLiO6 was distorted more strongly than octahedra of NbLiO6 when niobium atoms entered the vacant positions of lithium. The smallest changes in the bond lengths in the octahedra of the main motif and in the defect region as well as along the polar axis in the lithium niobate lattice were observed in the sample with a samarium concentration of 2.5 mol. %.

Structural Features of Nominally Pure Lithium Niobate Crystals Grown from Boron-Doped Charge

2020 ◽  
Vol 312 ◽  
pp. 128-133
Author(s):  
Nikolay Sidorov ◽  
Roman Titov ◽  
Natalya A. Teplyakova ◽  
Mikhail Palatnikov ◽  
Alexander Vjacheslavovich Syuy
Keyword(s):  
Crystal Structure ◽  
Lithium Niobate ◽  
Single Crystals ◽  
Czochralski Method ◽  
Structural Features ◽  
Structural Defects ◽  
Cation Sublattice ◽  
Structural Units ◽  
Boron Doped ◽  
Lithium Niobate Crystals

The features of the structure of single crystals LiNbO3:B3+ (0.12 and 0.18 wt %) grown by the Czochralski method from the mixture of different genesis were studied. It was found that boron is able to incorporate into the crystal structure of lithium niobate in a trace amounts (~ 10–4–10–5 wt %), decreasing the concentration of structural defects NbLi. Thus, ordering of structural units of the cation sublattice of lithium niobate crystals grown from a congruent composition melt approach in that of stoichiometric crystals.

The laser conoscopy of lithium niobate crystals of different composition

2016 ◽  
Author(s):  
O. Y. Pikoul ◽  
N. V. Sidorov ◽  
N. A. Teplyakova ◽  
M. N. Palatnikov
Keyword(s):  
Lithium Niobate ◽  
Lithium Niobate Crystals ◽  
Laser Conoscopy

Structural and Optical Homogeneity in Lithium Niobate Crystals of Low Photorefractivity

2015 ◽  
Vol 484 (1) ◽  
pp. 55-61
Author(s):  
N. V. Sidorov ◽  
M. N. Palatnikov ◽  
N. A. Teplyakova ◽  
A. A. Yanichev ◽  
A. A. Kruk ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Optical Homogeneity ◽  
Lithium Niobate Crystals

scholarly journals Structural particularities and optical properties of lithium niobate single crystals grown from the charge doped by boron.

2020 ◽  
Vol 11 (3-2020) ◽  
pp. 189-195
Author(s):  
R. A. Titov ◽  
◽  
N. V. Sidorov ◽  
N. A. Teplyakova ◽  
M. N. Palatnikov ◽  
...  
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Lithium Niobate ◽  
Distribution Coefficient ◽  
Single Crystals ◽  
Infrared Absorption ◽  
Cation Sublattice ◽  
Structural Units ◽  
Photoinduced Light Scattering ◽  
Laser Conoscopy

The analysis of structural particularities and optical properties of LiNbO3 : B (0,55, 0,69 and 0,83 mol. % B2O3) was performed by methods of Raman and photoinduced light scattering, infrared absorption and laser conoscopy. It has been established that the boron impurity brings to 1 the distribution coefficient of lithium and niobium in the growing process. Thus, LiNbO3: B crystals grown from a congruent melt approach the stoichiometric crystals in ordering the structural units of the cation sublattice and the Li / Nb ratio.

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