Yurii N. Kulchin

Photo-induced electric polarizability of Fe3O4 nanoparticles in weak optical fields

Using a developed co-precipitation method, we synthesized spherical Fe3O4 nanoparticles with a wide nonlinear absorption band of visible radiation. Optical properties of the synthesized nanoparticles dispersed in an optically transparent copolymer of methyl methacrylate with styrene were studied by optical spectroscopy and z-scan techniques. We found that the electric polarizability of Fe3O4 nanoparticles is altered by low-intensity visible radiation (I ≤ 0.2 kW/cm2; λ = 442 and 561 nm) and reaches a value of 107 Å3. The change in polarizability is induced by the intraband phototransition of charge carriers. This optical effect may be employed to improve the drug uptake properties of Fe3O4 nanoparticles.PACS33.15.Kr, 78.67.Bf, 42.70.Nq

Nontypical photoinduced optical nonlinearity of dielectric nanostructures

The recently discovered ultralow-threshold nonlinear refraction of low-intensity laser radiation in dielectric nanostructures has an atypical dependence on radiation intensity in the pulsedandcontinuousmodes.Wefirstcarryoutquantitativemeasurementsofthedependenceof the nonlinear response of liquid dielectric nanostructures on the low-intensity radiation and then devise a theoretical explanation. The theory suggests that the nonlinearity is of photoinduced nature instead of a thermal one and depends directly on the nanoparticles electronic structure and the relationship between permittivities of dielectric matrix and nanoparticles. C � 2011 Society

Quantum-Size States of a Particle inside the Deformed Nanosphere

In this paper we propose an original functional method which allows us to determine the effect of different deviations of nano-object shape on quantum characteristics of particles localized inside the nano-object. This method is ideologically similar to the perturbation theory, but the perturbation of the surface shape, rather than potential, is used. The results of analysis the quantum-size states of particles inside the nano-object with deformed sphere shape showed that the probability density of particle location is more sensitive to shape perturbations than surface energy spectrum and quantum states density are.

Dielectric Nano-Systems with Unique Optical Properties

The study of optical properties of Al2O3, SiO2, TiO2, and ZnO nanoparticles in weak optical fields is presented. We found that some nanoparticles have unique optical nonlinearity: The values of portions to nanoparticle refractive index and absorption coefficient increase to maxima, and then decrease to zero when the radiation intensity changes from 1 to 500 W/cm2. We estimated electron energy structures of nanoparticles and experimentally determined that such nonlinearity is directly related to peculiarities of the energy structure. We obtained a good fitting of theoretical results to the experimental ones (e.g. absorbance spectra of nanoparticles; the dependence of nanoparticle refractive index and absorption coefficient on radiation intensity).

Photonics of Heterogeneous Dielectric Nanostructures

Over last 20 years great scientific attention has been paid to nanostructures and nanocompo‐ sites based on nanoparticles of semiconductor materials (1eV<Egap<3eV) since they exhibit a wide range of nonlinear properties and can be used in various applied fields [1-5]. However, the history of active investigation of dielectric nanostructures’ properties started only recently [6-8]. These structures are the heterogeneous medium formed by liquid or solid dielectric ma‐ trices (e.g., polymer glasses and oils) and nanoparticles of dielectrics (Al2O3, SiO2, MgO, etc.).

Distributed Optical Fiber Systems for Structural Health Monitoring

The physical and mathematical principles of distributed optoelectronic measuring systems (MS) and networks for structural health monitoring are developed. There is developed a complete set of a theoretical and experimental data allowing designing a point and distributed phase optical fiber sensors (OFS) on the base of single-fiber multimode interferometers (SFMI) and Fabri—Perot fiber interferometers (FPFI). The principles of integrated measurements by the distributed and extended OFS and are investigated. There is developed the optimal topologies of tomography measuring networks and worked out the recommendations for type of sensitivity of used extended OFS which provide optimum conditions for the measuring data acquisition and for the reconstruction of distribution of controllable objects parameters. There are developed algebraic and neural network algorithms allowing to solve the reconstruction problem for various types of physical fields (PF) inside objects under monitoring, in conditions of measuring data incompleteness and in real time. The basic problems appearing at the distributed optoelectronic measuring networks and system’s parameters perfection and their large-scale practical application are determined.