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1.
Photoinduced optical and second-order non-linear optical effects in the interfaces separating In2O3–SiON (O/N ratio equals 1) films doped with A1, Sn and glass substrates were investigated using the photoinduced optical second harmonic generation. The photoinduced effective second-order optical susceptibility deff (at λ=1.76 μm) shows a good correlation with the linear optical susceptibility, particularly with the shift of the absorption edge. The maximal response of the photoinduced optical response signal was observed for the pump–probe delaying time of 34 ps. The performed experimental measurements indicate that the observed effects are mainly caused by the interface potential gradients on the border glass–In2O3–SiON film and by additional polarization due to insertion of the Al and Sn atoms. The observed phenomenon may be proposed as a sensitive tool for investigation of thin semiconducting interfacial layers and simultaneously such films may be used as materials for non-linear optical devices. 相似文献
2.
Photoinduced non-linear optical effects in large-sized (up to 25 nm) nanocrystallites (NC) of Ge-doped Bi12TiO20 (BTO:Ge) incorporated within olygoether photopolymer matrix have been studied. Photoinduced second harmonic generation (PISHG) was measured. Nd:YAG pulsed laser (λ=1.06 μm) was used as a source of photoinducing light. As a fundamental light source for the SHG and two-photon absorption, Er:LiYF4 laser (λ=2.065 μm) was used. We have found that with increasing IR pump power density, the output doubled frequency SHG signal (λ=1.03 μm) increases and achieves its maximum value at the pump power density about 0.45 GW/cm2 and NC size about 12 nm.The values of second-order optical susceptibilities were almost 20% larger than for the pure BTO NC single crystals. With decreasing temperature below 60 K, the SHG signal increases achieving maximal value at LHeT. 相似文献
3.
I.V. Kityk A. Ali Umar M. Oyama 《Physica E: Low-dimensional Systems and Nanostructures》2005,27(4):420-426
We have found that the gold nanoparticles on the ITO substrates might be considered promising materials for circularly polarized light-induced linear electrogyration (EG). The maximal achieved value of the EG susceptibility described by third-order axial tensor caused by probe circularly polarized light at a wavelength of 1060 nm was equal to about 13 deg/mm at pulsed electric field strength 30.0 V/cm with a duration of about 1 ms. We have revealed that the maximal EG coefficient is achieved for the samples possessing maximal resistivity. The investigated composites possess long-lived EG grating which decreases by not more than 12% after 120 min of laser treatment. Applying a non-circular pump light leads to the diminishing of the observed EG. 相似文献
4.
Fuks-Janczarek I Luc J Sahraoui B Dumur F Hudhomme P Berdowski J Kityk IV 《The journal of physical chemistry. B》2005,109(20):10179-10183
We have revealed a substantial enhancement of third-order optical figure of merits by the synthesis of a compact molecule possessing the tetrathiafulvalene (TTF) group with two backside C=O groups. Addition of the saturated methylene chain substantially suppresses the third-order optical figure of merits and even local optical hyperpolarizabilities at lambda = 532 nm. Another TTF-derivative molecule possessing ethylenic and acetylenic chains demonstrates large hyperpolarizabilities; however, generally, the figure of merit factor decreases due to the increasing optical losses as a consequence of enhanced linear absorption. At the same time, both of the chromophores have a large nonlinear optical response. General approaches for search and design of the third-order optical materials with improved properties are given. 相似文献
5.
P. Karasiński E. Gondek S. Drewniak I. V. Kityk 《Journal of Sol-Gel Science and Technology》2012,61(2):355-361
Following the spectral energy shift of the energy gap (blue shift) of the TiO2 sol–gel derived films we have evaluated diameters of the nanocrystallites. The TiO2 films were deposited by dip-coating technique. Two types of mesoporous films were studied: films with porosity ~16% and refractive
index (2.15 at wavelength 633 nm) and films with porosity ~46% and refractive index (1.61 at wavelength 633 nm). High porosity
and consequently low refractive index was achieved by adding the non-ionic surfactant Triton X-100 to the starting solution
as template. The principal goal of the work is to establish the influence of the Triton X-100 on the morphology as well as
to establish a possible correlation between the morphology and optical features of the titania films. The surface morphology
was explored using AFM method. And the energy gap was determined from the transmission spectra. Analysis of the blue energy
spectral shift is performed following the excitonic model. 相似文献
6.
Direct current conductivity of p-sexiphenyl films with 0.2-2.5 microm thickness deposited on glass substrates was investigated at temperatures between 10 and 300 K. The molecular dynamics simulations and quantum chemical calculations of the experimentally observed conductivity have shown that there exist at least three different states of the films effectively contributing to the observed features of the dc conductivity: conductivity caused by proper crystalline states, conductivity originated from amorphous-like inter-grain region and caused by grain's boundary. Comparison of the experimental data and theoretically calculated dependences shows that the main contribution to the observed dc conductivity gives grain boundaries between polycrystalline grains and amorphous-like background, though the latter possesses a relatively low part of the total volume. 相似文献
7.
Rheinstädter MC Kityk AV Rieger H Knorr K 《The European physical journal. E, Soft matter》2003,12(Z1):S47-S50
The out-of-equilibrium low-frequency complex susceptibility of the orientational glass methanol(73%)-beta-hydroquinone-clathrate is studied using temperature-stop protocols in aging experiments. Although the material does not have a sharp glass transition aging effects including rejuvenation and memory similar to the effects in spin glasses are found at low temperatures. 相似文献
8.
During bicolor optical treatment by two coherent laser beams from 25 ps Erbium-glass laser (λ = 1.54 μm), we have established substantial increase of effective optical second-order susceptibility near the critical temperature points corresponding to the glass structural transformation near 435 °C. The increasing Er3+ content favors substantial increase of the photoinduced optical second harmonic generation (SHG). This temperature dependence of the second-order optical susceptibilities detected by the SHG correlates well with the differential scanning calorimetric (DSC) measurements. At the same time, the effect exists only in a narrow temperature range (up to 12 °C) . There was not temperature hysteresis. Possible physical mechanisms of the phenomenon observed are discussed. 相似文献
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10.
A.S. Andrushchak B.V. Tybinka I.P. Ostrovskij W. Schranz A.V. Kityk 《Optics and Lasers in Engineering》2008,46(2):162-167
This paper deals with the technique for the refractive index measurements based on the interferometry of a rotated parallel plate (IRPP). The device consists of the Michelson interferometer, the sample rotation system and the optoelectronic registration system. A refractive index of parallel plates is determined by their rotation through measuring simultaneously a shift of interference fringes. Although the IRPP technique is known from long ago [Shumate MS. Appl Opt 1966;5:327] several considerable improvements have been done in order to improve the accuracy of the method. The measuring process is completely automated. The method has been tested on the model crystals of the lithium niobate giving the magnitudes for ordinary and extraordinary refractive indices as n0=2.2865±0.0007 and ne=2.2034±0.0007. A considerable increase of accuracy is reached in our case by an automation of the measuring procedure, development of a new software as well as implementing the interferometric method for a precise determination of a sample zero position. The automated refractometer is offered for use in research laboratories and industry. 相似文献