共查询到20条相似文献,搜索用时 15 毫秒
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A. A. Zabolotskii 《Journal of Experimental and Theoretical Physics》2008,106(2):404-412
Nonlinear optical properties of dye J-aggregates embedded in a one-dimensional periodic medium are analyzed theoretically and numerically. The effect of strain-induced exciton self-localization in a chain of monomers on nonlinear optical properties of the system is investigated for weakly and highly ordered J-aggregates. It is found that exciton self-localization in a periodic medium enhances light absorption and effective optical susceptibility. Optical bistability thresholds are examined for weakly and strongly excited dye J-aggregate thin films. It is shown that the threshold intensity of incident electromagnetic field is lower by more than an order of magnitude as compared to that for a homogeneous medium. 相似文献
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The problem of the transformation of a plane monochromatic wave by a finite-duration sequence of periodic rectangular pulses of the dielectric permittivity and magnetic permeability is solved exactly with integral equations. The expressions for the transformed component of the electric field at any point in space at an arbitrary time are derived and analyzed. 相似文献
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The generation of thermal waves in a one-dimensional structure with a sinusoidal variation in thermal diffusivity can be described
by an inhomogeneous Mathieu equation. An exact solution to the frequency-domain Mathieu equation can be found by using a variation
of parameters method to give the alternating component of the temperature along the structure. From the theory of Mathieu
functions a dispersion relation for the thermal waves is found, which does not display band gaps, but which shows damping
that departs from that for thermal waves in a uniform medium. 相似文献
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The problem of diffraction by simultaneously existing surface-profile and impedance gratings in the presence of resonance with a surface electromagnetic wave is examined. The problem is solved in an impedance approximation (Leontovich boundary condition) using Rayleigh's hypothesis. The solution method is based on the distinguishing of resonance fields, for which a finite system of equations is constructed. A proposed regular procedure for exclusion of nonresonance fields makes it possible to obtain a solution with any accuracy for any polarization of the incident radiation and orientation of the gratings. Specific results are given in a principal approximation for the case of several resonances in the first-order spectra.Scientific-Industrial Organization Metrology. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, Nos. 3, 4, pp. 234–245, March–April, 1992. 相似文献
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The evolution of an excitation front propagating on a nonuniformly curved surface is considered within the framework of a kinematical model of its motion. For the case of a surface with a periodically modulated curvature an exact solution of the front shape is obtained under the assumption of sufficiently small surface deformation. The results of the theoretical consideration are compared with the experimental data obtained with a modified Belousov-Zhabotinsky reaction in a thin nonuniformly curved layer. 相似文献
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Motivated by recent experiments on long‐lived magnetoplasmons in the presence of a perpendicular magnetic field, we investigate the dynamical dielectric response function of graphene in contact with a substrate using the random phase approximation. We add a periodically modulated magnetic field within the graphene plane and address both the inter and intra Landau band magnetoplasmons. Verification of the predicted magnetic modulation effects is possible by experiments analogous to those for the zero gap limit. 相似文献
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The rate of noise-induced escape from a metastable state of a periodically modulated overdamped system is found for an arbitrary modulation amplitude A. The instantaneous escape rate displays peaks that vary with the modulation from Gaussian to strongly asymmetric. The prefactor nu in the period-averaged escape rate depends on A nonmonotonically. Near the bifurcation amplitude A(c) it scales as nu proportional, variant(A(c) - A)(zeta). We identify three scaling regimes, with zeta = 1/4, -1, and 1/2. 相似文献
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A.A. Bulgakov 《Solid State Communications》1985,55(10):869-872
The existence of surface acoustic waves at the interface between a periodically layered and a homogeneous half-space is predicted. The reason for the arisal of such waves is the violation of the transnational symmetry pertinent to the periodic structure. The properties of the surface waves at a free boundary and a boundary with an elastic half-space are considered. 相似文献
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M. Trlifaj 《Czechoslovak Journal of Physics》1974,24(6):683-693
Formulae for persec probabilities of the nonradiative and radiative transformation of charge transfer excitons into molecular excitons in molecular organic crystals are derived and discussed. Numerical calculations are performed for solid naphtalene and anthracene. 相似文献