Publications on the project |
014 Optical limiting effects in nanostructured silicon carbide thin films |
Authors: | A.A. Borshch, V.N. Starkov, V.I. Volkov, V.I. Rudenko, A.Yu. Boyarchuk, A.V. Semenov | |
Summary: | We present the results of experiments on the interaction
of nanosecond laser radiation at 532 and 1064 nm with nanostructured silicon carbide thin films of different polytypes. We have found the effect of optical intensity limiting at both wavelengths. The intensity of optical limiting at wavelength 532 nm (I~ 106 W cm^–2) is shown to be an order of magnitude less than that at wavelength 1064 nm (I~ 107 W cm–2). We discuss the nature of the nonlinearity, leading to
the optical limiting effect. We have proposed a method for determining the amount of linear and two-photon absorption in material media. | |
Keywords: | optical limiting, nanostructured films, silicon carbide,
polytypes. | |
Edition: | Quantum Electronics | | | 2013,
1122-1126,Russian |
014 Femtosecond optical nonlinearity of Au nanoparticles under their excitation in nonresonant relative to surface plasmon conditions |
Authors: | M. Brodyn, V. Volkov, V. Lyakhovetsky, V. Rudenko, V. Styopkin | |
Summary: | Nonlinear optical response of Au island films to femtosecond laser pulses is studied in the vicinity but not exactly at the surface plasmon absorption peak (λsрr=560 nm). The
third order nonlinear optical susceptibility is shown to be 1,7×10-7 esu and 1×10-7 esu at the wavelengths 800 nm and 460 nm, respectively. Kinetics of the optical nonlinear response has been studied for wavelengths 400 nm and 800 nm.
It is believed that the origin of nonlinearity at the wavelengths is related to the free electron heating in the conduction band and their further thermalization via electronelectron
scattering, but at 400 nm the contribution to the nonlinear susceptibility because of interband d → s, p transitions is also possible. | |
Keywords: | | |
Edition: | Applied Physics B: Lasers and Optics | | | 2013,
567-572,English |
014 Third-order Optical Nonlinearity of Noble Metal Nanostructures |
Authors: | P.M. Tomchuk, M.S. Brodyn, V.I. Volkov, V.R. Lyakhovetskii | |
Summary: | Mechanisms of dissipative and nondissipative nonlinearities in
metal nanoparticles (NP) incorporated in a dielectric matrix
are theoretically considered. Infuence of the shape and the
size of NP on optical nonlinearities is studied. Since the dissipative nonlinearity is determined by hot electrons, the detailed analysis of factors defining the heating of electrons in
such systems (in particular, light absorption by small particles,
electron-lattice energy exchange in the particles, heat sink from
the particles into the matrix, etc.) is carried out. A concise
survey of experimental papers studying the cubic optical nonlinearity of the noble metal nanostructures (Au, Ag) is carried out. The survey is especially directed to show the influence of the geometrical parameters of NP, their environment, and the spectral position of the light wavelength against the plasmon resonance on the third-order susceptibility value. In particular, it is shown that the nonlinearity can be sufficiently enhanced not only in resonance with the surface plasmon, but also aside of it. The optical nonlinearity nature is discussed
as well. | |
Keywords: | | |
Edition: | | | | 2013,
50-69,Ukrainian |
014 The nanoparticle shape's effect on the light scattering cross-section |
Authors: | P.M. Tomchuk, D.V. Butenko | |
Summary: | In the framework of kinetic approach we develop a theory for light scattering by ellipsoidal metallic nanoparticles whose dimensions are less than those of a free electron path. In this case, the surface of the particle starts to play a dominant role in electron scattering. When the size of the particle decreases below the free electron path at least in one direction, the optical conductivity becomes a tensor quantity, and the diagonal components of this tensor define the half-widths of the plasmon resonances peaks. Thus, the effect of the particles' shape both on the frequencies of plasmon resonances and on their half-widths is considered. Additionally, the expression for a cross-section of the light scattering by a collection of chaotically oriented spheroidal nanoparticles is obtained and averaged over different directions of particles in the collection. Our results highlight the plasmonic properties of metallic nanospheroids, notably, the spectrum of the light scattering has two peaks at the frequencies of plasmon resonances even if there is no preferential direction in the collection of particles. | |
Keywords: | | |
Edition: | Surface Science | | | 2012,
1892-1898,English |
014 Nonlinear-optical and structural properties of nanocrystalline silicon carbide films |
Authors: | M. S. Brodyn, V. I. Volkov, V. R. Lyakhovetskii, V. I. Rudenko, V. M. Puzilkov, A. V. Semenov
| |
Summary: | The aim of this study is to investigate the nonlinearity of refraction in nanostructured silicon carbide films depending on their structural features (synthesis conditions for such films, substrate temperature during their deposition, concentration of the crystalline phase in the film, Si/C ratio of atomic concentrations in the film, and size of SiC nanocrystals formed in the film). The corresponding dependences are obtained, as well as the values of nonlinear-optical third-order susceptibility χ(3) for various silicon polytypes (3C, 21R, and 27R) which exceed the value of χ(3) in bulk silicon carbide single crystals by four orders of magnitude. | |
Keywords: | | |
Edition: | Journal of Experimental and Theoretical Physics | | | 2012,
235-242,Russian |
014 Nonlinear Plasma Dipole Oscillations in Spheroidal Metal Nanoparticles |
Authors: | Tomchuk P.M., Butenko D.V. | |
Summary: | The theory of nonlinear dipole plasma oscillations generated in a metal spheroidal nanoparticle by a laser-wave field has been developed. Approximate (to an accuracy of the cubic term) analytical expressions for the nanoparticle dipole moment have been obtained in the case of the laser field oriented along the spheroid rotation axis. | |
Keywords: | | |
Edition: | Ukranian Journal of Physics | | | 2011,
1111-1120,Ukrainian |
014 One-electron Optical Properties of a Nanorice with a Nonconcentric Core |
Authors: | V. V. Kulish, P. M. Tomchuk | |
Summary: | We investigate optical properties of nanoshells (small composite clusters composed of a dielectric core and a metal shell; contribution of the shell dominates in the optical properties of the whole cluster) far from plasmon resonance. In particular, nanoshells with the shape of a stretched rotation ellipsoid (nanorice) are considered. For such shell-type particle the electron wavefunction, the electron energy, the wavenumber spectrum, and the matrix elements of corresponding optical transitions were found. Using these quantities, the classical optical conductivity of such shells (the quantum effects are not considered) and the quantum optical conductivity (relevant addendums for the classical conductivity that are caused by the quantum effects like the electron spectrum discreteness) were found. Oscillating nature of the dependence of these addendums on the incident light frequency is established. The optical conductivity expressions are generalized for the case of a nanorice particle with a weak nonconcentricity. | |
Keywords: | nanorice;nanoshells;optical conductivity;small clusters;spectrum quantization | |
Edition: | Particle & Particle Systems Characterization | | | 2012,
238-252,English |
014 Study of the spectral and nonlinear optical properties of nanostructured gold films. |
Authors: | M.S. Brodyn, P.M. Tomchuk, V.I. Styopkin, V.R. Liakhovetskyi, V.I.Volkov, A.O. Borshch, V.I. Rudenko, M.V. Volovyk | |
Summary: | | |
Keywords: | | |
Edition: | | | | 2014,
69-74,Russian |
The events in the framework of the project |
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014 Executant:Institute of Physics, Department of Physics and Astronomy, Section Physical, Engineering and Mathematics 1. Physics of nanostructures Purpose:The main aims is:
- to develop physical principles of laser-optical methods in the nanosecond range for the realization of optical diagnostics plasmon nanostructures using the research of the nonlinear optical properties and the nature of nonlinearity in metal (Au, Ag, Pd, Cu) nanostructured films on dielectric substrates;
- to detect nonlinear dependence of the optical response on the size and shape of metal nanoparticles under exсitation by ultrashort laser pulses Expected results:Release of new product: material Stage 1:Development and improvement of technology for planar metallic nanostructures. Creating gold, silver, palladium and copper samples with different size and shape of metal nanoparticles. Characterization of synthesized samples: spectroscopy, atomic force and electron microscopy, nonlinear optical parameters. Theoretical analysis of the results. Stage 2:The research of nonlinear optical response of metallic nanostructures. The measurements of cubic nonlinear optical susceptibilities depending on the size and shape of metal nanoparticles under nanosecond laser pulses Stage 3:The study of the dynamics of nonlinear optical response of metallic planar structures. The time measuring of response and relaxation of optical changes under the excitation of powerful laser radiation Stage 4:The research of nonlinear optical response of metallic nanostructures under femtosecond laser excitation. The measurements of cubic nonlinear optical susceptibilities depending on the size and shape of metal nanoparticles Stage 5:Continued research in view of the results obtained during the previous phases: modernization of the synthesis technology of metal nanofilms to obtain the necessary parameters. The measurements of nonlinear optical parameters. The theoretical analysis of the experimental results.
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