Optical elements for near infrared spectra region from high optical quality lithium niobate single crystals

1994 ◽  
Author(s):  
Dmitry Y. Sugak ◽  
Andrej O. Matkovskii ◽  
E. A. Korobenko ◽  
Anatolij I. Mikhalevych ◽  
Ivan M. Solskii ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Single Crystals ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Optical Quality ◽  
Optical Elements ◽  
High Optical Quality ◽  
Near Infrared Spectra

scholarly journals ANALYSIS OF METHODS FOR SYNTHESIS OF A BORON-DOPED LITHIUM NIOBATE CHARGE USED FOR GROWING SINGLE CRYSTALS

2021 ◽  
pp. 750-759
Author(s):  
Софья Михайловна Маслобоева
Keyword(s):  
Lithium Niobate ◽  
Single Crystals ◽  
Solid Phase ◽  
Synthesis Method ◽  
Lithium Carbonate ◽  
Optical Quality ◽  
High Optical Quality ◽  
Boron Doped ◽  
Boron Dopant ◽  
A Charge

Проведен анализ известных методов синтеза шихты ниобата лития, легированной бором, которая используется при выращивании монокристаллов высокого оптического качества методом Чохральского. Установлено, что способ гомогенного легирования (шихта получается из прекурсора NbO :B и LiCO) по сравнению с твердофазным (шихта получается из смеси LiCO: NbO : HBO ) позволяет выращивать кристаллы LiNbO: B с более однородным распределением в них примеси бора, а также в объеме расплава, при этом упрощаются технологические режимы, устанавливаемые при росте кристаллов. В работе впервые рассмотрен жидкофазный метод синтеза шихты, исключающий стадию прокалки гомогенизированной смеси пентаоксида ниобия и карбоната лития. Результаты имеют важное значение при выборе технологии выращивания легированных бором монокристаллов ниобата лития для конкретных областей техники. Known methods of a boron doped lithium niobate charge synthesis were analyzed. Such a charge is applied for the growth by Czochralski of single crystals with high optical quality. Homogeneous doping (the charge is obtained from precursor NbO:B and LiCO) was compared with solid phase doping (the charge is obtained from the mixture LiCO: NbO: HBO). Homogeneous doping was determined to help produce LiNbO: B crystals with a more uniform distribution of a boron dopant, boron distributes more uniform in the melt volume; technological regimes established during crystal growth become easier. For the first time the paper considers liquid-phase charge synthesis method; the method excludes the stage of annealing of homogenized mixture of niobium pentoxide and lithium carbonate. Results are crucial for the choice of technology at growing of boron doped lithium niobate crystals for exact areas of technics.

UV-Visible Faraday Rotators Based on Rare-Earth Fluoride Single Crystals: LiREF4 (RE=Tb, Dy, Ho, Er and Yb), PrF3 and CeF3

2013 ◽  
Vol 582 ◽  
pp. 194-197
Author(s):  
Valentyn Vasyliev ◽  
Encarnacion G. Villora ◽  
Masaru Nakamura ◽  
Yoshiyuki Sugahara ◽  
Kiyoshi Shimamura
Keyword(s):  
Single Crystals ◽  
Figure Of Merit ◽  
Near Infrared ◽  
Vacuum Ultraviolet ◽  
Wavelength Region ◽  
Optical Quality ◽  
High Optical Quality ◽  
Figures Of Merit ◽  
Earth Fluoride ◽  
Uv Visible

High optical quality LiREF4(RE = Tb3+, Dy3+, Ho3+, Er3+and Yb3+), PrF3and CeF3single crystals have been grown by the Czochralski technique. Their magneto-optical properties have been measured and analyzed in detail in the ultraviolet-visible wavelength region, and their figures of merit as Faraday rotators have been determined. CeF3presents superior properties above 300 nm, showing a figure of merit higher than that of the reference material, terbium-gallium-garnet, which is nowadays used in the visible-near infrared. PrF3is the best rotator for the 220-300 nm range. Towards shorter wavelength and in the vacuum ultraviolet, it is shown that the LiREF4crystals are unique rotators.

Rapid Determining Contents of the Rhubarb Anthraquinones Compounds by Support Vector Machines Modeling based on Near Infrared Spectra

2020 ◽  
Vol 16 ◽  
Author(s):  
Linqi Liu ◽  
JInhua Luo ◽  
Chenxi Zhao ◽  
Bingxue Zhang ◽  
Wei Fan ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Mean Squared Error ◽  
Rapid Determination ◽  
Partial Least Square ◽  
Least Square ◽  
Support Vector ◽  
Near Infrared Spectra ◽  
Aloe Emodin ◽  
Relative Differences

BACKGROUND: Measuring medicinal compounds to evaluate their quality and efficacy has been recognized as a useful approach in treatment. Rhubarb anthraquinones compounds (mainly including aloe-emodin, rhein, emodin, chrysophanol and physcion) are its main effective components as purgating drug. In the current Chinese Pharmacopoeia, the total anthraquinones content is designated as its quantitative quality and control index while the content of each compound has not been specified. METHODS: On the basis of forty rhubarb samples, the correlation models between the near infrared spectra and UPLC analysis data were constructed using support vector machine (SVM) and partial least square (PLS) methods according to Kennard and Stone algorithm for dividing the calibration/prediction datasets. Good models mean they have high correlation coefficients (R2) and low root mean squared error of prediction (RMSEP) values. RESULTS: The models constructed by SVM have much better performance than those by PLS methods. The SVM models have high R2 of 0.8951, 0.9738, 0.9849, 0.9779, 0.9411 and 0.9862 that correspond to aloe-emodin, rhein, emodin, chrysophanol, physcion and total anthraquinones contents, respectively. The corresponding RMSEPs are 0.3592, 0.4182, 0.4508, 0.7121, 0.8365 and 1.7910, respectively. 75% of the predicted results have relative differences being lower than 10%. As for rhein and total anthraquinones, all of the predicted results have relative differences being lower than 10%. CONCLUSION: The nonlinear models constructed by SVM showed good performances with predicted values close to the experimental values. This can perform the rapid determination of the main medicinal ingredients in rhubarb medicinal materials.

Discrimination of transgenic tomatoes based on visible/near-infrared spectra

2007 ◽  
Vol 584 (2) ◽  
pp. 379-384 ◽  
Author(s):  
Lijuan Xie ◽  
Yibin Ying ◽  
Tiejin Ying ◽  
Haiyan Yu ◽  
Xiaping Fu
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Near Infrared Spectra ◽  
Transgenic Tomatoes

Mid and near Infrared Study of Carbohydrates by Canonical Correlation Analysis

1993 ◽  
Vol 1 (2) ◽  
pp. 99-108 ◽  
Author(s):  
P. Robert ◽  
M.F. Devaux ◽  
A. Qannari ◽  
M. Safar
Keyword(s):  
Correlation Analysis ◽  
Infrared Spectra ◽  
Canonical Correlation ◽  
Near Infrared ◽  
Sugar Content ◽  
Infrared Region ◽  
Total Sugar ◽  
Mid Infrared ◽  
Total Sugar Content ◽  
Near Infrared Spectra

Multivariate data treatments were applied to mid and near infrared spectra of glucose, fructose and sucrose solutions in order to specify near infrared frequencies that characterise each carbohydrate. As a first step, the mid and near infrared regions were separately studied by performing Principal Component Analyses. While glucose, fructose and sucrose could be clearly identified on the similarity maps derived from the mid infrared spectra, only the total sugar content of the solutions was observed when using the near infrared region. Characteristic wavelengths of the total sugar content were found at 2118, 2270 and 2324 nm. In a second step, the mid and near infrared regions were jointly studied by a Canonical Correlation Analysis. As the assignments of frequencies are generally well known in the mid infrared region, it should be useful to study the relationships between the two infrared regions. Thus, the canonical patterns obtained from the near infrared spectra revealed wavelengths that characterised each carbohydrate. The OH and CH combination bands were observed at: 2088 and 2332 nm for glucose, 2134 and 2252 nm for fructose, 2058 and 2278 nm for sucrose. Although a precise assignment of the near infrared bands to chemical groups within the molecules was not possible, the present work showed that near infrared spectra of carbohydrates presented specific features.

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