A5023707106- Nonlinear Optical Materials Studies
- Laser-Ablation Synthesis of Nanoparticles
- Diamond and Carbon-based Materials Research
- Nonlinear Optical Materials Research
- Material Dynamics and Properties
- Liquid Crystal Research Advancements
- Quantum Dots Synthesis And Properties
- Silicon Nanostructures and Photoluminescence
- Plant and animal studies
- Fractional Differential Equations Solutions
- Near-Field Optical Microscopy
- Copper-based nanomaterials and applications
- Diffusion and Search Dynamics
- Nonlinear Dynamics and Pattern Formation
- Surfactants and Colloidal Systems
- Photochemistry and Electron Transfer Studies
- Ion-surface interactions and analysis
- Spectroscopy and Quantum Chemical Studies
National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”
2013-2023
Institute of Physics
2013
Institute of Semiconductors
1988
In the simplest realization of Brownian motion, a colloidal sphere moves randomly in an isotropic fluid; its mean squared displacement (MSD) grows linearly with time $\textitτ$. motion orientationally ordered fluid, nematic, is anisotropic, MSD being larger along axis molecular orientation, called director. We show that at short scales, anisotropic diffusion nematic becomes also anomalous, growing slower (subdiffusion) and faster (superdiffusion) than The anomalous occurs scales correspond...
Single particle tracking data are usually analyzed in terms of the mean square displacement (MSD) which exhibits, case Brownian particles undergoing anomalous diffusion, a time dependence that is slower (subdiffusion) or faster (superdiffusion) than linear one. The velocity autocorrelation function (VAF), directly related to underlying dynamics host medium brings about can then be obtained as second derivative MSD. We examine possibility obtain (MVAF) from trace and analyze its relation true...
Nonlinear optical properties of thin polycrystalline PdO films are investigated using the Z-scan technique and a 800 nm 180 fs laser, whose wavelength is significantly longer than absorption edge at 500 nm. Cubic nonlinear susceptibility Re χ(3) = +1.1 × 10−6 esu (n2 5.6 10−9 cm2/W) coefficient β ≈ 5 10−5 cm/W determined. The positive sign implies intraband carrier (predominantly holes) relaxation dynamics Kerr effect as underlying mechanisms. Relaxation time refractive nonlinearity...
Mechanisms for anomalous diffusion of colloidal particles in a nematic environment are theoretically investigated. It is shown that thermal fluctuations the director may couple to translational and orientational motions particles, which leads diffusion. Both superdiffusion, when mean square displacement increases with time faster than linearly, subdiffusion, this dependence slower linear, possible. For micrometer-sized effects expected on millisecond scales.
We report on [Formula: see text]-scan investigations of the nonlinear optical properties thin pyrolytic carbon films and two- three-layer graphene films, utilizing an 800[Formula: text]nm pulsed laser generating ultrashort 180[Formula: text]fs pulses. analyze sign magnitude refraction absorption in these materials, given contradictory results this respect literature. In particular, we find that changes with changing light intensity concomitant subtle absorption, a behavior not reported...
The article presents results of the parameters optical cubic nonlinearity (OCN) thin amorphous Cu2O films under 532 and 1064 nm pulsed laser excitation. were synthesized on SiO2 (silica) substrates by reactive deposition technique at 293 or 800 K a different oxygen pressure 1, 3, 5 Pa. bandgap was determined from absorption spectra. 1 3 Pa demonstrated positive OCN, whereas obtained K, Pa, negative OCN. largest nonlinear refractive index n2 = + 1.35 × 10−6 cm2/W for film Under excitation,...
Abstract Nonlinear polarization spectroscopy, a new type of laser spectroscopy solids, is used for the investigation cubic crystals with reorienting centers. This technique based on self‐induced change light (SICLP) applied determination fine parameters F A (Li)‐, (Na)‐, 2 ‐centers in KCl. It shown that mechanism phonon‐induced mixing wave‐functions belonging to nondegenerate and degenerate excited electronic states responsible SICLP manifestation KCl ‐centers.