The development of the electronic industry, with the further miniaturization of electronic components and the use of new materials puts forward increasingly stringent requirements for the quality, reliability and competitiveness of products. All this, in turn, dictates the creation of new technologies and technological processes. The microprocessing laser technologies at R&D production facility "Istok" named after Shokin " for the period 2003-2018, a series of modern automated laser technological installations of the "Caravel" type was created on the basis of industrial lasers and laser systems based on copper vapors and precision three-coordinate tables. This equipment with the diameter of the processing light spot of 10–20 μm and the peak power density of 109-1011 W/cm2 allows for efficient and high quality processing of foil (0.01-0.2 mm) and thin-sheet (0.2-1 mm) metal and the large range of non-metallic materials of microwave products.
The main approximations for calculation of effective parameters of inhomogeneous media are Bruggeman effective medium approximation and Maxwell Garnett model, which are currently widely used in the description of composites containing various nanostructured objects. In this paper we consider a simple approach to these approximations, allowing to embrace the most general case of statistically anisotropic media with particles of arbitrary internal structure, and also to clarify their physical meaning. The type of result essentially depends on the choice of "effective cells" used in estimating the field and induction values averaged over the volume.
Polyvinylchloride films were obtained and studied by optical methods after thermolysis. A strong increase in the intensities of the absorption spectra and a shift in the long-wave region with increasing thermolysis time are established. These facts can be explained by the increase in the number and size of the conjugated carbon double bonds. The optical absorption method is sufficiently informative to determine the relative change in the number of conjugated carbon double bonds and their sizes. The amount of conjugated carbon double bonds in polyvinylchloride films is estimated as a function of the thermolysis time. The shift of the absorption spectra to a longer-wavelength region is analyzed with increasing conjugated carbon double bonds with increasing thermolysis time studied.
The nonlinear response of metal oxide nanoparticles obtained by the acoustic plasma method is measured in aqueous disperse systems at a wavelength of 532 nm. Induced absorption is detected in the Cu2O, WO3 and ZnO disperse systems, and bleaching is detected in the Fe2O3 system. The real and imaginary parts of nonlinear third-order susceptibilities are determined.
Colloidal solutions of Ag silver nanoparticles were studied in the presence of Eu3+ ions and in the absence of their. Silver nanoparticles were created by the method of green synthesis using an aqueous solution of mint. Optical and electronic spectroscopy have been used to explore the interaction of these ions with silver nanoparticles.
The effect of the tungsten coating on the photoelectric and electrophysical properties of electron-silicon samples after gold diffusion was analyzed. The trap levels associated with tungsten atoms, with a tungsten complex + vacancy, and with an oxygen + vacancy complex were detected. In samples of silicon doped with gold, both with and without a tungsten coating, the resistivity increased by 2-3 orders of magnitude, which indicates the creation of additional energy centers associated with gold and gold complexes caused by tungsten. At the same time, the time of nonstationary relaxation photoconductivity has greatly decreased, which also indicates the creation of additional recombination centers and trap levels.
By the method of green synthesis, silver nanoparticles were obtained in colloidal solutions. The solutions were modified with thulium ions. Using the method of electron microscopy and optical method, the properties of silver nanoparticles obtained are studied. The influence of change in concentration of the solution of mint and thulium ions on the properties of colloidal silver nanoparticles was studied.
Recently, research has been developing on nanoscale objects (a group of atoms) for which the concept of dielectric constant has a conventional meaning and therefore requires refinement and even analysis. In this paper we analyze the change in the intensity of Raman scattering of nanoobjects placed on a flat substrate. Some variants were shown for which the scattering can vary by more than an order of magnitude. In particular, on an ideal metal substrate, the region of antinode of a standing light wave upon reflection does not extend to the near-surface layer in which the nanoobject is located. And for this reason the Raman scattering decreases by more than an order of magnitude. Conditions are shown under which a decrease in Raman scattering from nanoobjects can be compensated and even increased.
N. Labin, A. Chursin, V. Paramonov, V. Klimenko, G. Paramonova, I. Kolokolov, K. Vinogradov, L. Betina, N. Bulychev, Yu. Dyakov, R. Zakharyan, M. Kazaryan, K. Koshelev, O. Kosheleva, A. Grigoryants, I. Shiganov, V. Krasovskii, V. Sachkov, P. Plyaka, I. Feofanov, C. Chen
The paper revealed the using of industrial production equipment ALTI "Karavella-1", "Karavella-1M", "Karavella-2" and "Karavella-2M" precision components of IEP production [1–4]. The basis for the ALTI using in the IEP have become the positive results of research and development of technologies of foil (0.01–0.2 mm) and thin sheets (0.3–1 mm) materials micromachining by pulsed radiation CVL [5, 6]. To assess the micromachining quality and precision the measuring optical microscope (UHL VMM200), projection microscope (Mitutoyo PV5100) and Carl Zeiss microscope were used.
The effect of sediment flotation was observed in dispersion of graphene oxide flakes with Ag-particles deposited thereon in the aqueous-organic (containing dimethylformamide) under the visible light action, with subsequent stabilization of the dispersion, which does not occur in the absence of Ag-particles. The main reason for this laser light induced movement of sediment graphene oxide flakes may be associated with the appearance of small bubbles. The further development of this approach seem to be able to estimate the of graphene flakes photoactivity with different activating particles.
Research on CVL installations with an average power of 20–25 W of cutting and drilling has shown wide range of applications of these lasers for micromachining of metals and a wide range of non-metallic materials up to 1–2 mm. From the analysis indicated that peak power density in the focused light spot of 10–30 μm diameter must be 109 –1012 W/cm2 the productivity and quality micromachining, when the treatment material is preferably in the evaporative mode micro explosions, followed by the expansion of the superheated vapor and the liquid. To achieve such levels of power density, a minimum heat affected zone (5– 10 μm) and a minimum surface roughness of the cut (1–2 μm), the quality of the output beam of radiation should be as high. Ideally, to ensure the quality of the radiation, the structure of CVL output beam must be single-beam, diffraction divergence and have at duration pulses τi = 20–40 ns. The pulse energy should have low values of 0.1–1 mJ at pulse repetition rates of 10–20 kHz. Axis of the radiation beam instability of the pattern to be three orders of magnitude smaller than the diffraction limit of the divergence. The spot of the focused radiation beam must have a circular shape with clear boundary, and a Gaussian intensity distribution.
The influence of thermolysis time on the absorption spectra of partially thermally dehydrochlorinated polyvinyl chloride in acetophenone solution is studied. Strong increase in the optical density Dλ of the dehydrochlorinated PVC samples is caused by the increasing amount N-C=С- and the length of chains of conjugated double bonds of carbon -C = C-. It is noted that the optical density Dλ first increases linearly with dehydrochlorination time and then reaches saturation. The estimation of amount of double conjugated carbon bonds in 1ml versus thermolysis time t is given, which varies between N-С=С- = 4·1017 – 7.4·1018 for t from 40 to 420 minutes. The effective capture cross section of a photon on conjugated double bonds of carbon for dehydrochlorinated PVC solution in acetophenone is estimated, which was about 10-17 cm2 . The analysis is done of the absorption curves «red» shift to longer wavelengths with growth of N-С=С- upon increase of thermolysis time. It is noted that the dependence of the optical density on the wavelength in this range is well described by a simple exponential function.
This work reports on the theoretical and experimental research of photophysical properties of hybrid nanostructures
based on gold nanoparticles (AuNp) covered by phthalocyanine (Pc) layer. We focused on the theoretical treatment of Pc
molecular absorption and luminescence properties. We found out optimal sizes for the hybrid structure core when the
maximum of Pc shell molecular absorption is achieved. Optimal core sizes for enhancement of the molecular
luminescence were also obtained. AuNp-Pc hybrid structure with average core radius of 10 nm and Pc shell thickness of
2.5 nm were experimentally synthesized. The calculation results were compared with the experimental data, so we
obtained well coincidence between each other.
Gold nanoparticles were prepared by laser ablation in water. Size separation was realized by sedimentation and
centrifuging. The interaction of the protein (bull serum albumin - BSA) and gold nanoparticles was investigated in water
solution. The obtained samples were characterized by approximation of optical absorption spectra in terms of Drude
model for metal cores with dielectric shells.
The composite material of gold nanocrystals in porous glass matrix was obtained by chemical deposition. Optical spectra were fitted using Drude model. Real and imaginary parts of third-order nonlinear optical susceptibility were separately measured in surface plasmon resonance area using Z-scan technique and 20 ps 539 nm laser pulses. The obtained values of Reχ(3) was -4.12±0.8×10-8 esu and Imχ(3) was -4.28±0.4×10-7 esu. It was shown that the differences of absorption and refraction nonlinearities from field effect predictions can be satisfactorily explained by local field correction.
Optical properties and third order optical nonlinearity of liquid metal colloids prepared by laser ablation in water and ethanol are investigated. It was found out that water colloids took stable state after partial sedimentation with changing of ONL sign during sedimentation process. The optical absorption spectra are interpreted within the framework of Drude model for metallic particles with taking into account the effect of nanoparticles sizes on optical properties. Stable state is explained by colloid of small Ag particles with presumable oxide shell. The sizes of small Ag particles were calculated and nonlinear optical absorption parameters were measured by z-scan technique.
Nonlinear optical interaction of first and second harmonies of YAG laser in thin layer of high density packed silicon nanocrystals have been investigated. The second harmonic was polarized perpendicular to first. In the experiment the tow color single beam Z-scan technique have been used. The interaction of optical beams with different wavelengths and polarization was observed. Action of first harmonic to the second and vice versa lead to changing the sign of the nonlinear susceptibility coefficients as for first and second harmonics.
The huge non-linear optical response have been observed for the silicon nanocrystals monolayer on the silver surface in the normal back scattering configuration. The competition of non-linear saturation and absorption was observed. The value of the non-linear optical absorption coefficient is coming to the 2 X 10(superscript -3) cm/W. The structure of the monolayer was tested by atomic force microscope and average thickness have been estimated on the basis of the surface plasma waves resonance in Kretschmann configuration. It was observed the enhancing of non-linear susceptibility by effect of the surface of noble metal.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.