Stimulated Raman scattering (SRS) in barium nitrate powder was studied in two temporal modes: excitation by laser pulses of 11 ns and 30 ps from the room temperature to the temperature of liquid nitrogen. For the first time, an increase in the efficiency of SRS conversion by two orders of magnitude was observed when the sample temperature was lowered from room temperature to the temperature of liquid nitrogen. The maximum achieved value of the conversion efficiency was 30 percent. Temporal characteristics of all the SRS components registered in transient mode were measured. The detected effect of the pump energy influence on the delay time of the first Stokes component can be used for measuring the nonlinear parameters of the medium.

Random lasing in Raman active material – barium nitrate powder – has been registered in two temporal regimes: nanosecond and picosecond. Stimulated Raman scattering (SRS) in Ba(NO3)2 for picosecond excitation has been shown to have much lower threshold and spectrum containing more components than for nanosecond excitation opposite to the case of a bulk medium. In picosecond regime SRS intensity increased with temperature decreasing and redistributed in favor of the higher order components. SRS pulse duration in picosecond regime was estimated to be in the range 16.5-22 ps. High conversion efficiency of SRS in barium nitrate powder in picosecond regime and its larger stability under laser impact than for bulk samples gives possibility to use it as an active material in Raman converters.

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.

Experiments of the electrical field impact on Ti: Sapphire crystal optical parameters are reported. Luminescence spectral amplitude reduction and bandwidth increase with the red-shift of the maximal amplitude after high voltage application are demonstrated.

The polarization of a laser crystal by an external electrical field generates new possibilities for the wide control of laser parameters, and can expand applications for existing lasers and also create a new line of the laser devices. The direct impact of external electrical fields on the laser solid state gain media was previously estimated using as an example a Ti:Sapphire (Ti:Sa) crystal. It was demonstrated that the metal-ligands distances displacement in this crystal under the external electrical field is comparable to distortions caused by a mechanical pressure of 150 kbar, measured in early experiments. In this letter, the experimental results of the electrical field impact on (Ti:Sa) crystal optical parameters are reported. These experiments demonstrate a reduction in the luminescence spectral amplitude and an increase in bandwidth with the red-shift of the maximal amplitude after high voltage application.

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.

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.

Laser pulses interaction with tobacco mosaic virus (TMV) in Tris-HCl pH7.5 buffer and in water has been investigated. 20 ns ruby laser pulses have been used for excitation. Spectrum of the light passing through the sample was registered with the help of Fabri-Perot interferometer. In the case of TMV in water we observed in the spectrum only one line of the exciting laser light, for TMV in Tris-HCl pH7.5 buffer second line appeared, corresponding to the stimulated low-frequency Raman scattering (SLFRS) on the breathing radial mode of TMV. SLFRS frequency shift by 2 cm-1, (60 GHz), conversion efficiency and threshold are measured for the first time to the best of our knowledge.

Cupric oxide nanoparticles with average size of 213.2 nm, were synthesized in acoustoplasma discharge for investigating their vibrational properties. The low-frequency acoustic mode in cupric oxide (CuO) nanoparticles has been studied by stimulated low-frequency Raman scattering (SLFRS). SLFRS conversion efficiency, threshold and frequency shift of the scattered light are measured.

Stimulated low-frequency Raman scattering (SLFRS), caused by laser pulses interaction with the radial breathing modes of tobacco mosaic virus (TMV) in Tris-HCl pH7.5 buffer was registered. SLFRS frequency shift, conversion efficiency and threshold are measured.

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 study of nonlinear effects, caused by nanosecond laser pulses’ impact on the frozen ZnS nanoparticles’ suspension, is presented. Laser pulses excite strong nanoparticles’ coherent vibrations in the near-terahertz range which lead to different nonlinear effects: X-ray emission, stimulated low-frequency Raman scattering, and luminescence. X-ray emission was observed as bright spots on the special X-ray film. This provides evidence that an X-ray propagates with narrow beams. Stimulated low-frequency Raman scattering is a result of light scattering by acoustic vibrations of nanoparticles. Its frequency shift corresponds to the nanoparticles’ eigenvibration frequencies and depends on the sample material and particle’s dimension. It was measured with the help of a Fabri-Perot interferometer in the range of dispersion \(16.67\,\hbox {cm}^{-1}\). For ZnS, the first Stokes component frequency shift is equal to 465 GHz. Under excitation by 20 ns ruby laser pulses, the luminescence of the frozen ZnS nanoparticles’ suspension was observed in two bands located at 480 nm and 510 nm. Its duration was more than 3 s.

In this Letter we report on experimental observation of stimulated low-frequency Raman scattering (SLFRS) in gold and silver nanoparticle suspensions excited by 20 ns ruby laser pulses, SLFRS propagated in forward and backward directions with a maximum conversion efficiency up to 20%. Frequency shift for silver nanoparticle suspension was found to be 0.33 THz and for gold nanoparticle suspension 0.435 THz. This type of stimulated scattering of light can be used as an effective source of biharmonic pumping for solving a large number of practical tasks.

We present experimental results on the interaction of pulsed laser radiation with ZnS-quantum-dot aqueous suspensions. We detect luminescence in the blue spectral range as well as narrow beams of X-ray radiation. We describe the experimental conditions of X-ray generation and discuss the triboluminescence as a possible mechanism of the emission.

Experiments on the observation of a brightness-amplified image of an object through a masking arc discharge are presented. The copper-vapor laser active medium was used as an image brightness amplifier. It is shown that the image quality does not worsen under plasma background illumination.

The chemical vapor deposition (CVD) technique is applied for synthesizing diamond films and plates of large size (∼100 mm) and high quality. In the given work, we consider one of the diamond-structure dimensional processing and microprocessing methods based on the application of a Cu laser, whose irradiation can be focused to a small spot and also used for the intensification of the image brightness in an optical system, which is able to process ∼106 points of an object for one (∼10 ns) or a few pulses. The characteristics of processed surfaces of polycrystalline diamond films and plates are given.

Синтезом алмаза из газовой фазы (Chemical Vapor Deposition – CVD) получают алмазные пленки и пластины большого размера ( 100 мм) и высокого качества. В данной работе рассматривается один из методов размерной обработки и микрообработки алмазных структур, основанный на применении лазера на парах меди, излучение которого можно сфокусировать в пятно малых размеров, а также использовать для усиления яркости изображения в оптической системе, способной за один импульс ( 10 нс) или за небольшое их число обработать 106 точек объекта. Приводятся характеристики обработанных участков поликристаллических алмазных пленок и пластин.

In this paper, we present the results of the experimental study of the spectral line emission of cadmium and mercury atoms in the pulsed discharge afterglow in gas mixtures containing vapors of bromides of these metals, hydrogen, and helium buffer gas. It was shown that the population of triplet resonance levels is controlled by recombination of positive metal ions and negative bromine ions.