This paper discusses an approach to the search for the starting approximations when inverse optical problems are to be solved to determine the refractive indices and thicknesses of dielectric films on substrates. It is proposed to use reflection spectra obtained at different angles of incidence of light on the sample, from which the refractive indices and thickness of the film are computed from the location of the intensity extrema. In monochromatic null ellipsometry, the measurement of the polarization parameters of light at different angles of incidence makes it possible to determine the refractive index and ellipsometric thickness for each angle. The starting approximation for the thickness for solving the inverse problem in ellipsometry, based on the data for all the angles of incidence used for light on the sample, is obtained from the optical thickness of the film, determined from the reflection spectra at small angles of incidence.

Tridentate azomethine ligands with N2O and N3donor atoms and their copper complexes have been synthesized and characterized. Magnetochemical measurements in the temperature range of 5–300 K show...

Представлен обзор спектральных комплексов для атомно-эмиссионного спектрального анализа, производимых компанией «ВМК-Оптоэлектроника»: «Гранд-Глобула», «Гранд-Кристалл» и «Экспресс» - для прямого атомно-эмиссионного спектрального анализа твердых металлических и порошковых проб; «Гранд-Поток» - для экспресс-анализа порошков методом просыпки-вдувания; «Гранд-Эксперт» и «Фаворит» - для экспресс-анализа металлов и сплавов; установки искрового пробоотбора «Аспект» - для анализа металлических образцов с помощью ИСП-АЭС и ИСП-МС; «Экспресс-Ойл» - для прямого анализа масел; «Павлин» - для экспресс-определения натрия, лития, калия, кальция, бария, цезия, рубидия в растворах. Приведены их состав и технические характеристики спектрометров.

Modern small-sized spectrometers are mainly designed by the Czerny–Turner scheme with a flat diffraction grating or, if the goal is to obtain the maximum aperture at the expense of resolution, by the scheme with a concave diffraction grating. In such spectrometers, the spectrum is registered by photodiode array. In this work, we provide an overview of characteristics of the compact spectrometers developed by our group. These spectrometers use caseless linear photodiode arrays for spectrum registration that eliminates the reflection of radiation from the cover glass of the photodiode array and reduces stray light. The tightness of the housing of spectrometers prolongs their service life. The parameters of the spectrometer modifications designed according to the Czerny–Turner scheme are given. The main advantage of the spectrometer of this type is the low stray light inside the device and the same spectral resolution throughout the spectral range. Aberrations limit the working aperture in the Czerny–Turner scheme to 1/6. The scheme with a flat field allows operation with a larger working aperture. Three modifications of the spectrometer have been developed according to this scheme; a description of their main parameters is given. The results of experimental comparison of the light gathering power and spectral resolution of spectrometers with different optical schemes, as well as the examples of their application, are presented. Devices designed according to the Czerny–Turner scheme are used in atomic emission and atomic absorption spectral analysis and in spectrophotometry for registration of absorption spectra of condensed media. The spectrometers with flat field are used for recording luminescence and Raman spectra of minerals. The developed compact spectrometers can work in a spectral range of 190–1100 nm with the width of the recorded spectral range from 70 to 1000 nm; the best spectral resolution is 0.1 nm, the stray light level is less than 0.05%, and the maximum measured optical density exceeds 3. Owing to a large working aperture of 1 : 2.1, the flat field spectrometers have an increased light gathering power.

In 2023, optical spectrometers Grand were included in the Russian State Register of Measuring Instruments under No. 89108-23 as a tool for measuring the mass fractions of analytes in natural and industrial materials. These spectrometers are manufactured by VMK-Optoelektronika company in ten modifications, nine of which are atomic emission spectrometers and one is an atomic absorption spectrometer: Atomic emission spectrometers a. Grand-Globula, Grand-Kristall, and Grand-Express arc and spark discharge spectrometers for direct (without preliminary chemical preparation) analysis of powder samples and metals; b. Grand-Potok arc discharge spectrometer for rapid analysis of powder samples using the spill-injection method; c. Grand-Expert and Grand-Favorit vacuum argon spark discharge spectrometers for rapid analysis of metals and alloys; d. Grand-MP nitrogen microwave plasma spectrometer and Grand-ICP inductively coupled argon plasma spectrometer for analysis of liquid samples; e. Grand-Pavlin flame emission spectrometer for determination of alkali and alkaline earth elements in solutions. Grand-AAS high-resolution continuum source electrothermal atomic absorption spectrometer for simultaneous multielement determination in liquids. Atomic emission spectrometers have various spectrum excitation sources based on almost all atomization and excitation methods known in atomic emission spectrometry. Grand-AAS atomic absorption spectrometer is the world's first commercial instrument that allows the simultaneous determination of more than 40 elements in a liquid in one electrothermal atomization cycle with analytical performance close to that of modern electrothermal atomic absorption spectrometers for the sequential determination of elements.