The gravitational waves predicted by the general theory of relativity and detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) have typical frequencies in the range of 30 ... 300 Hz. Current theories of gravity predict the existence of high-frequency gravitational waves with frequencies of 10 ... 100 MHz, including those of cosmological origin, induced by quantum fluctuations of the scalar field at the stage of cosmological inflation in the early Universe.Multi-beam optical resonators, in particular the Fabry-Perot interferometers, can be used to detect high-frequency gravitational waves. When using multi-beam optical resonators, it is possible to use the phenomenon of low-frequency optical resonance, which allows us to have a selective response to the gravitational wave effect. The gravitational-optical resonance in a multi-beam interferometer occurs if the condition is fulfilled that an integer number of half-waves of gravitational radiation is along the length of the resonator.The use of a multi-beam interferometer to detect high-frequency gravitational waves does not require the creation of a complex system for decoupling mirrors used for gravitational antennas operating in the low-frequency part of the spectrum. This is due to the fact that the frequency of mechanical vibrations of the interferometer mirrors is significantly less than the frequency of the gravitational wave.The paper considers possible optical schemes of a high-frequency gravitational antenna: based on the traditional Michelson interferometer, in the arms of which two Fabry-Perot interferometers are available, and on the basis of the Mach-Zehnder optical scheme, where Fabry-Perot interferometers can be made in the form of two perpendicular arms, with reflecting mirrors at the bend of the beam. The advantage of the second scheme is that three photo-detectors, one being main and two others being auxiliary, can be used, and there is a possibility to detect radiation transmitted by Fabry-Perot interferometers.To prove that detection of high-frequency gravitational waves is possible, a potential sensitivity of the high-frequency gravitational antenna has been estimated in the paper.

The use of Raman spectroscopy for the rapid analysis of chemical substances is considered. To reduce the time of the analysis, it is proposed to use a Fourier-transform spectrometer based on a static Michelson interferometer, in which a spatial scan of the interferogram occurs. Two schemes of implementation of a model of a static Fourier-transform spectrometer are represented: with a matrix photodetector device (PD) that makes it possible to obtain better spectral resolution and with a linear PD, which is more sensitive. The Raman spectra are recorded in the spectral range of 800 to 1050 nm, which makes it possible to perform the analysis in the daytime. A laser with wavelength λ = 785 nm and power of 1.5 W is used as the source of excitation radiation. The interferograms obtained on both models of Fourier-transform spectrometers are presented; the Raman spectra of the following test substances are restored: 1,4-bis(5-phenyl-2-oxazolyl)benzene (POPOP, C24H16N2O2), stilbene (C14H12), chloroform (CHCl3), and ethanol (C2H5OH), and their correlation matrices are presented.

The authors analyze opportunity of application of the Fabry Perot interferometers for detection of high-frequency gravitational wave perturbations occurred during the initial stage of the formation of the Universe. It is shown that at usage of the phenomenon of low-frequency optical resonance there is opportunity of tuning of laser interferometric gravitational wave antenna for detection of high-frequency perturbations. The calculation formulas for determination of the spectral sensitivity of the Fabry Perot interferometer are obtained and the level of the minimum detectable spectral density of fluctuations of the space-time metric is evaluated. We have the advantage of this version of laser interferometric gravitational wave antenna due to absence of necessity to host mirrors of the interferometer on free masses

The authors analyze opportunity of application of the Fabry – Perot interferometers for detection of high-frequency gravitational wave perturbations occurred during the initial stage of the formation of the Universe. It is shown that at usage of the phenomenon of low-frequency optical resonance there is opportunity of tuning of laser interferometric gravitational wave antenna for detection of high-frequency perturbations. The calculation formulas for determination of the spectral sensitivity of the Fabry – Perot interferometer are obtained and the level of the minimum detectable spectral density of fluctuations of the space-time metric is evaluated. We have the advantage of this version of laser interferometric gravitational wave antenna due to absence of necessity to host mirrors of the interferometer on free masses.

Рассмотрена методика бесконтактного анализа веществ и устройство, его реализующее. Для построения устройства был предложен статический фурье-спектрометр, в основе работы которого лежит явление интерференции в клине. Описана методика получения и обработки спектров излучения. Регистрация интерференционных картин происходит с использованием источников возбуждающего излучения с длинами волн 280 и 315 нм. Рассчитаны основные характеристики оптической системы и приведены спектры излучения тестовых веществ.

We have considered a technique for noncontact analysis of compounds and a device for its realization. To construct the device, we have proposed a static Fourier-transform spectrometer that is based on the phenomenon of interference in a wedge. A procedure for obtaining and processing emission spectra has been described. Interference patterns are recorded using sources of excitation radiation of 280 and 315 nm. Basic characteristics of the optical system have been calculated, and emission spectra of test objects have been presented.

We propose a technique and algorithm for processing interferograms obtained with a static Fourier spectrometer. Spectra of secondary radiation from certain compounds are obtained in the visible and near-UV spectral ranges upon excitation by different radiation sources. We present and discuss results of experimental data processing.

Excitation of synthetic opal with 337.1-nm nitrogen laser pulses gives rise to a persistent afterglow, lasting 15 s at 10 K. The afterglow spectrum correlates with the emission spectrum of opal observed earlier under excitation with UV light-emitting diodes. The effect can be understood in terms of the peaks in the density of photon states near the edges of the photonic band gap in photonic crystals.

Transmission spectra of synthetic opal photonic crystals have been measured in the wavelength range of their band gap. The results indicate that the minimum-transmission wavelength depends on the lattice constant of opal and, hence, on the position of the photonic band gap. For synthetic opal samples on the order of 1 mm in thickness, the experimentally determined transmittance in the wavelength range of the photonic band gap does not exceed a fraction of a percent.

We developed a method for detecting traces of foreign components in water and analyzing the microstructure of water. The method is based on studies of the characteristics of secondary emission arising in aqueous media under excitation by radiation of ultraviolet lasers and light emitting diodes. A new type of cuvette (capillary cuvettes) for studying the secondary-emission in molecular media was elaborated. The cuvettes enable the study of aqueous solutions at small concentrations of the components; they enable one to recognize the type of molecular compound present in aqueous media, in view of the photoluminescence spectra.

We have measured emission spectra of opal photonic crystals infiltrated with ferroelectrics and phosphors. At a given excitation wavelength, the emission spectra of the infiltrated opals differ markedly from the spectrum of plain opal: the emission bands are redshifted, and extra peaks are present. The infiltration effect on the emission spectrum of the opal matrix can be accounted for by the shift of the photonic band gap.

Novel nonlinear optical effects - photonic flame effect (PFE)(1,2) and stimulated globular scattering (SGS)(3) - have been discovered. SGS was observed both in forward and backward direction. Pure opal crystal, consisting of the close-packed SiO2 globules with diameter 200 nm, and crystal with pores, filled with molecular liquid, have been studied. Two Stokes components, shifted from the exciting light frequency by 0.4 - 0.6 cm(-1), have been observed in SGS. Photonic flame effect consisted in the appearance of the few seconds' duration emission in blue-green spectral range under 20 ns ruby laser pulse excitation.