Options for using ordered 3D arrays of photonic crystals for the generation of gigahertz, optical, and neutron radiation upon interaction with a beam of high-energy electrons are considered. The optical emission spectra of photonic crystals produced in the interaction with a beam of relativistic electrons are presented. Experiments were carried out to obtain 2D images of objects in gamma and neutron fluxes generated in the interaction of an electron beam with a photonic crystal material. Various neutron generating targets are considered, for which the corresponding neutron yields were calculated. The characteristics of electromagnetic and neutron fields obtained in the experiment are also presented.

An anomalous (more than ten times) increase in the SRS intensity in liquids under picosecond excitation is detected as ultrasonic exposure on a medium is turned-on. The physical mechanism of the detected phenomenon is discussed. It is presumably associated with the formation of random feedback caused by the formation of inhomogeneities in liquid under ultrasonic excitation.

Passive Q-switching of a ruby laser using stimulated low-frequency Raman scattering of light has been implemented. Suspensions of submicron dielectric and metal particles were used inside a laser cavity as a Q-switching device. The Q-factor of the resonator changed due to stimulated inelastic scattering by the coherent acoustic vibrations of particles. It has been shown that the pulse duration can vary from tens of nanoseconds to microseconds by changing the characteristics of the submicron system. The advantage of this method of passive Q-switching in comparison with a saturable dye is shown.

Оценивается однородность структуры мезопористого фотонного кристалла по электронной фотографии его поверхности. Предложен метод разбиения поверхности кристалла на домены с помощью корреляционной обработки цифрового изображения. В качестве основных численных характеристик упорядоченности системы пор рекомендованы следующие параметры: средний и максимальный линейные размеры домена, а также доля регулярных структур в образце. По этим и по ряду дополнительных параметров можно различать даже очень близкие по качеству структуры. Проведено сравнение изображений из различных источников. Ключевые слова: алюминиевая фольга, фотонные кристаллы, поры, однородность структуры, цифровое изображение.

Homogeneity of the mesoporous photonic crystal structure is estimated by an electron photograph of its surface. A method of crystal surface division into domains by correlation processing of the digital image is proposed. The following parameters are recommended as main numerical characteristics of pore system ordering: the average and maximum linear sizes of the domain, as well as the fraction of regular structures in the sample. Using these and some additional parameters, one can distinguish even qualitatively very close structures. Images from different sources are compared.

We report the results of an experimental study on the temporal and spectral response of organic liquids luminescence excited by UV radiation at liquid-nitrogen temperature. The afterglow at liquid-nitrogen temperature was detected with a decay time of the order of 1000 ms. We have revealed that the afterglow appears at a definite temperature of about 80 K.

We experimentally register stimulated low-frequency Raman scattering (SLFRS) in the suspension of brome mosaic virus (BMV) in phosphate buffer with very high conversion efficiency. We identify two components of the SLFRS spectrum as the breathing and quadrupole modes of BMV and determine damping characteristics and gain factors for these modes. We show that, using the core–shell model for BMV and taking into account the influence of the environment, the acoustic properties of individual components of such a composite nanosystem can be determined. Thus, we define the sound velocity in the RNA core of BMV, in view of spectral characteristics of SLFRS.

The interaction of electromagnetic radiation with nanoscale particles systems (including suspension of metallic dielectric and semiconductor nanoparticles, biological nanostructures, etc.) can lead to various non-linear effects, in particular, to the stimulated low-frequency Raman scattering (SLFRS). It can provide important information about investigated system elastic properties. In the present study low-frequency vibrational modes in different biological nanoparticles systems were investigated, such as tobacco mosaic viruses (TMV), two types of potato viruses (PVX and PVA), cauliflower mosaic virus (CaMV), human and bovine serum albumin (HSA and BSA) in Tris-HCl pH7.5 buffer and in water. 20 ns ruby laser pulses were used for excitation. SLFRS frequency shifts, corresponding to acoustic eigenfrequencies of the samples were registered by Fabri-Perot interferometers. Conversion efficiency and threshold were also measured for the first time. SLFRS can be applied for nanoobjects identification and effective impact on biological nanoparticles systems.

The transmission spectrum of a holographic sensor (silver nanograins embedded in a polymer matrix) is shown to be well described by expressions for the Rayleigh light scattering and absorption by silver nanograins. The optical characteristics of the medium are determined in the Maxwell Garnett approximation. In the presence of a holographic structure, a dip appears in the spectrum. A possibility of obtaining the approximating curves depends on the approximation range. The spectra are well approximated both in the presence and in the absence of an interference structure. For different approximation ranges, the dip parameters coincide despite the values of the background parameter associated with absorption can differ significantly.

We observe stimulated low-frequency Raman scattering (SLFRS) caused by laser pulse interaction with acoustic vibrations of nanoparticles in water suspensions of LaF3 nanoparticles. We show that frequency shifts of the scattering correspond to the eigenfrequencies of nanoparticles vibrations. LaF3 nanoparticles were synthesized in the presence of glycine by a double jet precipitation technique at various initial concentrations of reagents. We investigate the morphologies and particle sizes as well as size distributions of the particles prepared using transmission electron microscopy (TEM) and dynamical light scattering (DLS). In view of the absorption spectroscopy, we show that the reaction system components and products have no absorption in the visible region, including λ = 694.3 nm. From the luminescence spectroscopy, we find also that they do not emit at λ = 694.3 nm excitation.

The review gives the main points of the current state of holographic sensors development based both on researches of foreign scientists and on the results of the only group in Russia dealing with this problem. Holographic sensors are a new class of diagnostic devices that are thick-layered holograms recorded instead of gelatin in a special hydrogel that reacts to the presence of certain substances in liquid and gas mixtures. The cross-links of the hydrogel matrix are tuned to the test component of the mixture, and the more the hydrogel layer of the sensor shrinks or swells, the higher the component concentration is. This mechanism makes it possible to quantify the concentration of a particular substance. The paper describes the main properties, advantages, measuring capabilities, and possible applications of the holographic sensors. In this case, water quality studies are very promising, both in urban water supply systems and for monitoring ecosystems in natural reservoirs. Moreover, with the holographic sensors it is possible to measure the hardness and acidity of water, as well as pollution with ions of heavy metals, bacteria and their spores, etc. To monitor the atmosphere, there are specially designed holographic sensors that allow determining the content of combustible hydrocarbon gases in air, and air humidity and temperature. The sensors can also be widely used in medicine in order to determine the concentrations of a wide range of compounds contained in biological fluids. The review discusses in detail the problems that arise when analyzing the level of glucose in blood plasma and serum and draws the comparison of holographic sensors with existing diagnostic tools. We consider the possibilities of using digital imaging technology, including smartphones, as an alternative to spectrometric registration of the sensor response because, compared with spectrometers, widespread digital photographic equipment significantly simplifies the measurements and reduces their cost. This is very important for the operative monitoring of environmental parameters, especially in the field. The review details the problems of measuring the wavelength of the light reflected from the sensor for different types of data available in digital cameras (image formats). Based on the arguments available in the literature, the authors substantiate the importance of designing holographic sensors for the growing sector of the express diagnostic market in practical medicine.

Stimulated low-frequency Raman scattering has been registered in different plant viruses, placed in water or Tris- HCl pH7.5 buffer. Frequency shifts of the scattered light components have been measured with the help of Fabri-Perot interferometers. High efficiency of the scattering is evidence of the effective excitation of gigahertz vibrations in viruses.

The interaction of laser pulses with the Cauliflower mosaic virus (CaMV) in a Tris-HCl pH7.5 buffer is investigated. 20 ns ruby laser pulses are used for the excitation. Spectra of the light passing through the sample and reflected from it are registered with the help of a Fabri–Perot interferometer. Stimulated low-frequency Raman scattering (SLFRS) in a CaMV suspension is registered. The SLFRS frequency shift, conversion efficiency and threshold are measured for the first time, to the best of our knowledge.

We register stimulated low-frequency Raman scattering (SLFRS) caused by laser-pulse interaction with nanoparticle acoustic vibrations in an ethanol suspension of sodium chloride nanoparticles and measure the SLFRS conversion efficiency and threshold. Frequency shifts of scattered light from the exciting light frequency are situated in the gigahertz range. We show that the frequency shifts increase with decrease in the nanoparticle sizes.

The results of the study of interdiffusion of two liquids, obtained using the holographic recording scheme with a nonstationary reference wave with the frequency linearly varying in space and time are compared with the results of correlation processing of digital photographs, made with a random background screen. The spatio-temporal behaviour of the signal in four basic representations (‘space – temporal frequency’, ‘space – time’, ‘spatial frequency – temporal frequency’ and ‘spatial frequency – time’) is found in the holographic experiment and calculated (in the appropriate coordinates) based on the background-oriented schlieren method. Practical coincidence of the results of the correlation analysis and the holographic double-exposure interferometry is demonstrated.

The statistical error of correlation measurement of the shift is estimated using the binary image model. The influence of image properties on the accuracy of subpixel measurements of the position of the maximum of the correlation peak is studied. Recommendations for the choice of parameters of the image and correlation algorithm are given.

We compare results of the colorimetric method use for measurements of the wavelength distribution from digital images in standard formats (BMP, JPEG, TIFF) and in RAW-format. It is shown that with the use of the last one the operating range is several times larger (up to 455-625 nm).

We discuss a possibility of using the standard commercial digital camera as a metering device in correlation, colorimetric and intensity measurements. It is shown that after extracting linear data from the camera matrix and carrying out an appropriate calibration procedure the camera characteristics are comparable with those of technical cameras.