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By combining analytical and numerical approaches, we study resonantly enhanced second-harmonic (SH) generation by individual high-index dielectric nanoparticles made of centrosymmetric materials. Considering both bulk and surface nonlinearities, we describe second-harmonic nonlinear scattering from a silicon nanoparticle optically excited in the vicinity of the magnetic and electric dipole resonance...
Thin (300 and 600 nm) epitaxial silicon layers were deposited on R-plane sapphire wafers by CVD technique using SiH4 and SiCl4 mixture gas diluted by hydrogen. Quality parameters of epitaxial silicon on sapphire (SOS) wafers were studied by means of XRD, AFM, UV scattering and surface PV methods. Resistivity profiles of layers were measured. Quality of SOS in dependence on initial growth (up to 80–100...
We develop the asymptotic theory of third-harmonic generation from silicon nanoparticles driven by optically-induced Mie resonances and analyze the multipolar nature of the generated electromagnetic fields. We propose the approaches for directing the resonantly enhanced nonlinear scattering by spherical and disk-shaped particles, excited in the vicinity of the magnetic dipolar resonance. Our analytical...
The use of photothermal Zernike phase-contrast filter for measuring the absorption of the medium proposed. Results of numerical simulation are given. It is shown that the efficiency is comparable to the imaging scheme that uses linear filters, with a significant simplification of the process of its adjustment.
The increase in the prevalence of allergic diseases requires the active implementation of the capabilities of modern technology in the process of providing health care for children with asthma. The paper describes the system for remote monitoring for asthma patients receiving treatment atthe Scientific Center of Children Health. We describe the method of estimating of the state of patients, the method...
Novel types of volume Bragg gratings with enhanced parameters were recorded in PTR glass. They were used for efficient spectral beam combination of high power multimode semiconductor lasers with high spectral density of 1 nm/channel.
The second harmonic generation and two-photon luminescence from a colloidal solution of spherical gold nanoparticles at wavelength tuning of exciting radiation is studied in experiments. The measured polarization and spectral characteristics of the second harmonic and two-photon luminescence demonstrate that the observed nonlinear optical response is determined by the dimers that constitute several...
This paper describes existing methods of calculating pressure, density, temperature and viscosity of the liquid-gas mixture through the height of the tubing. New method for parameters calculation of the liquid-gas mixture along production well, which is based on the Sakharov method used in the ice-resistance stationary platform simulator is presented.
The present paper concerns the development and approbation of the method of resonant near-field microwave to-mography with regard to problems on early diagnostics of melanoma and other skin neoplasms.
Modern mathematics is becoming more attractive for the education system because of the possibility to adapt its fundamental structures in applications and development of cognitive and creative abilities of the individual. Such subject are related to fractal geometry, which was "revived to life" by B. Mandelbrot beginning with the 70s of XX century. In this paper, we give applications of...
We numerically simulated two-photon luminescence at the near-filed interaction of a gold nanoparticle and a conductive atomic-force microscope tip (AFM) using FDTD calculation of electric field distribution. Comparison of the results of numerical simulation with the experimental data [1] gives information on the shape and orientation of the nanoparticles with a resolution surpassing that of conventional...
This work presents the development of a noninvasive technique of investigating biological tissues, which is based on the method of resonant near field microwave tomography. Being new in medical practice, this method allows one to determine subsurface distributions of dielectric permittivity and conductivity of a medium by using the results of measuring the impedance of small antennas which are located...
The self-action effects of the laser radiation incident on metal nanoparticles of spherical shape are analyzed within the framework of a free-electron model and a phenomenological description of the nonlinear electrodynamic properties of the metal surface. Analytical expressions are obtained for the nonlinear addition to the field-induced dipole moment of a nanoparticle at the fundamental frequency...
We study the initiation of a pulsed microwave discharge in atmospheric air by a plasma channel induced by intense femtosecond laser pulses. It is shown that the electric field threshold for the initiated discharge is lowered compared with the self-discharge by about a factor of two, from 25 to 12 kV·cm−1. Channelling of the atmospheric-pressure microwave discharge in the direction of the plasma filament...
We introduce a concept of resonant tunneling photonic nanotransistor which makes possible mutual control of cross-cut light flows. The idea of this concept is based upon strong resonant interaction between phase-matched tunnelly coupled quasi-localized eigenmodes of nonlinear planar dielectric waveguide and incident beam. We demonstrate that by means of variation of input beam or guided wave intensities...
We show that transverse local narrowing of metal-dielectric-metal (MDM) plasmonic slot waveguide can squeeze plasmon mode in transverse direction (along the slot) up to several tens of nanometers. We consider the two types of narrowing: step-wise and smooth and calculate the structure and dispersion of 2D plasmonic eigenmodes in both cases. We also find the minimal possible scales of the plasmon nanolocalization.
This work is devoted to studying the possibilities of using a femtosecond laser facility and a scanning atomic-force microscope (AFM) for nonlinear optical diagnostics. The developed technique ensures an optical resolution of 30 nm for gold nanoparticles. It is shown that the presence of the AFM tip significantly affects the nonlinear optical response of separate gold nanoparticles.
One of the actual and quickly developing spheres of modern dynamics is the turbulence theory in superfluids involving Bose-Einstein condensate (BEC) of atoms of alkaline elements. At studying the turbulence in BEC it is important to know how do vortices form and interact with each other, and what part do they play in process of transition from a condensate to a turbulence state.
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