排序方式: 共有54条查询结果,搜索用时 527 毫秒
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E. A. Vinogradov V. O. Kompanets Yu. E. Lozovik Yu. A. Matveets S. V. Chekalin 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(5):677-679
The relaxation of nonequilibrium charge carriers in ZnSe films on metal substrates has been investigated by the femtosecond spectroscopic pump-supercontinuum probe method. Upon subgap and overgap excitations of ZnSe, red and blue photoinduced frequency shifts for the interference cavity modes in ZnSe films on chromium have been revealed. Such shifts and features of the relaxation times are explained by photoinduced changes in the boundary conditions and optical thickness of the microcavity. 相似文献
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Kenji Harada Masahide Itoh Igor N. Kompanets Hiro Matsuda Alexander V. Parfenov Nobuyuki Tamaoki Toyohiko Yatagai 《Optical Review》1998,5(2):89-92
We propose a new type of spatial light modulator using nonlinear organic polymer film as a phase modulation element. Using polymer poly-Disperse Red-19 Toluendiiso-cyanate, a more than 150:1 contrast ratio has been realized for electrical addressing in transverse geometry. 相似文献
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V. P. Kandidov E. O. Smetanina A. E. Dormidonov V. O. Kompanets S. V. Chekalin 《Journal of Experimental and Theoretical Physics》2011,113(3):422-432
The formation of conical emission of supercontinuum during filamentation of femtosecond laser pulses with central wavelengths
in a wide range is studied experimentally, numerically, and analytically. The frequency-angular intensity distribution of
the spectral components of conical emission is determined by the interference of supercontinuum emission in a filament of
a femtosecond laser pulse. The interference of supercontinuum emission has a general character, exists at different regimes
of group velocity dispersion, gives rise to the fine spectral structure after the pulse splitting into subpulses and the formation
of a distributed supercontinuum source in an extended filament, and causes the decomposition of the continuous spectrum of
conical emission into many high-contrast maxima after pulse refocusing in the filament. In spectroscopic studies with a tunable
femtosecond radiation source based on a TOPAS parametric amplifier, we used an original scheme with a wedge fused silica sample.
Numerical simulations have been performed using a system of equations of nonlinear-optical interaction of laser radiation
under conditions of diffraction, wave nonstationarity, and material dispersion in fused silica. The analytic study is based
on the interference model of formation of conical emission by supercontinuum sources moving in a filament. 相似文献
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Optics and Spectroscopy - The advantages of using the method of laser coloration for investigation of specific features of filamentation in homogeneous transparent dielectrics are described. The... 相似文献
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Yu. M. Yevdokimov S. G. Skuridin V. I. Salyanov S. V. Semenov E. V. Shtykova L. A. Dadinova O. N. Kompanets E. I. Kats 《Optics and Spectroscopy》2017,123(1):56-69
The character of packing of double-stranded DNA molecules in particles of liquid-crystal dispersions formed as a result of the phase exclusion of DNA molecules from aqueous salt polyethylene glycol solutions has been estimated by comparing the circular dichroism (CD) spectra of these dispersions recorded at different osmotic pressures and temperatures. It is shown that the first cycle of heating of dispersion particles with hexagonally packed double-stranded DNA molecules leads to the occurrence of abnormal optical activity of these particles, which manifests itself in the form of a strong negative CD band, characteristic of DNA cholesterics. Moreover, subsequent cooling is accompanied by a further increase in the abnormal optical activity, which indicates the existence of the “hexagonal → cholesteric packing” phase transition, controlled by both the osmotic pressure of the solution and its temperature. The result obtained can be described in terms of “quasi-nematic” layers composed of orientationally ordered DNA molecules in the structure of dispersion particles. There are two possible ways of packing for these layers, which determine their hexagonal or cholesteric spatial structure. The second heating → cooling cycle confirms these results and is indicative of possible differences in the packing of double-stranded DNA molecules in the hexagonal phase, which depend on the osmotic pressure of the solution. 相似文献
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Yu. M. Yevdokimov S. G. Skuridin V. I. Salyanov S. V. Semenov P. N. Sol’ev V. T. Valuev-Elliston F. V. Vereshchagin D. P. Chulkov O. N. Kompanets 《Optics and Spectroscopy》2017,122(2):194-201
We propose a version of the theory describing the circular dichroism spectra of cholesteric liquidcrystal dispersion particles of double-stranded DNA. The basis of the theory is the concept of absorption of electromagnetic waves by large molecular systems. The effect of physical parameters of dispersion particles on their circular dichroism is theoretically determined. It is experimentally demonstrated that circular dichroism can be used as a convenient tool for creating an optical analytical system for the determination of biologically active compounds that interact with DNA molecules. 相似文献
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B. N. Mironov V. O. Kompanets S. A. Aseev A. A. Ischenko I. V. Kochikov O. V. Misochko S. V. Chekalin E. A. Ryabov 《Journal of Experimental and Theoretical Physics》2017,124(3):422-428
The generation of coherent optical phonons in a polycrystalline antimony film sample has been investigated using femtosecond electron diffraction method. Phonon vibrations have been induced in the Sb sample by the main harmonic of a femtosecond Ti:Sa laser (λ = 800 nm) and probed by a pulsed ultrashort photoelectron beam synchronized with the pump laser. The diffraction patterns recorded at different times relative to the pump laser pulse display oscillations of electron diffraction intensity corresponding to the frequencies of vibrations of optical phonons: totally symmetric (A 1g ) and twofold degenerate (E g ) phonon modes. The frequencies that correspond to combinations of these phonon modes in the Sb sample have also been experimentally observed. 相似文献
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D. G. Poydashev V. O. Kompanets V. N. Lokhman S. V. Chekalin E. A. Ryabov 《Journal of Experimental and Theoretical Physics》2017,125(6):1034-1041
The dynamics of dissociation of (IF2CCOF) n , (CF3I) n , and (CH3I) n clusters induced by femtosecond UV radiation (λ = 266 nm) is investigated. The method of UV excitation and photoionization probing (λ = 400 nm) combined with the time-of-flight mass spectrometry is applied. It is found that clusters excited to Rydberg states lying below the ionization threshold are decomposed, as a result of subsequent relaxation processes, giving rise to free neutral molecules. A mechanism of electronic–vibrational relaxation process is proposed, and data on the characteristic times of different stages of this process are obtained. 相似文献
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