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ABSTRACT: We theoretically investigate the coupling of light with magnetoexcitons in near-surface quantum wells under the action of a static electric field parallel to the well plane. Such a coupling is here described within the Stahl’s real-space density-matrix approach. In particular, we have solved the system of equations for the coherent-wave amplitude and the electromagnetic fields for InGaAs/GaAs quantum-well heterostructures and calculated their reflectivity spectra. We have found that a parallel electric field of magnitude ∼ 1–10 kV/cm can considerably alter the line shape of optical spectra due to the resonant coupling of light with magnetoexcitons having nonzero angular momentum projection. Besides, we have studied the changes in the profile of the optical spectra as the thickness of the heterostructure cap layer is decreased until it is comparable with the exciton radius and, consequently, the interaction of the magnetoexciton with the sample surface becomes strong.
Journal of Applied Physics 01/2011; 109(1):014303-014303-8. · 2.17 Impact Factor
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ABSTRACT: Exact analytic formulas for calculating the effective permittivity, permeability, and crossed magnetoelectric tensors for photonic crystals in the long-wavelength limit are presented. The formulas are valid for arbitrary Bravais lattice and form of inclusions, which can be dielectric, magnetic, or chiral. We have applied them to study the optical anisotropy of homogenized magnetodielectric three-dimensional photonic crystals, which can be induced by the type of Bravais lattice or the form of the inclusion even in the case when the photonic crystal is composed of isotropic materials. It is established that the electromagnetic modes, propagating in such anisotropic magnetodielectric metamaterials, are extraordinary, unlike the modes in homogenized nonmagnetic dielectric composites, where at least one mode is ordinary.
Journal of Applied Physics 12/2009; · 2.17 Impact Factor
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ABSTRACT: We investigate theoretically the coupling of exciton with light in a one-dimensional photonic crystal. The unit cell of the crystal consists of two alternating layers, namely a metallic layer and a semiconductor one. The frequency-dependent dielectric function of the metal is described by the Drude model, whereas for the semiconductor we use a nonlocal excitonic dielectric function. The polariton dispersion for s-polarized modes in the metal-semiconductor photonic crystal is compared with that for a dielectric-semiconductor photonic crystal. Because of the metal layers, a low-frequency gap appears in the photonic band structure. The presence of the semiconductor gives rise to photonic bands associated with the coupling of light with size-quantized excitón states. At frequencies above the longitudinal exciton frequency, the photonic band structure exhibits anticrossing phenomena produced by the upper exciton-polariton mode and size-quantized excitons. It is found that the anticrossing phenomena in the metal-semiconductor photonic crystal occur at higher frequencies in comparison with the dielectric-semiconductor case.
Journal of Nanoscience and Nanotechnology 01/2009; 8(12):6584-8. · 1.56 Impact Factor
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ABSTRACT: We present a theoretical study of the optical properties of excitons in symmetric and asymmetric bulk and near-surface double quantum wells (DQWs) under the action of an external magnetic field oriented along the growth direction. The coupling of magnetoexcitons with light in the semiconductor heterostructure is described with Stahl’s real-space density-matrix approach. After solving the system of equations for the coherent wave amplitude and the electromagnetic fields, we calculate optical spectra (reflectivity and absorption) for specific GaAs/AlGaAs DQWs. Our results for the absorption of bulk symmetric DQWs are compared with those obtained by Vera and Barticevic [F. Vera and Z. Barticevic, J. Appl. Phys. 83, 7720 (1998)]. The effect of the surface-magnetoexciton interaction upon the reflectivity and absorption for near-surface DQWs is analyzed. It is established that such an interaction alters the symmetry or asymmetry of the DQWs, and therefore, the resonance structure of their optical spectra is noticeably modified as the thickness of the cap layer is reduced.
Journal of Applied Physics 10/2007; · 2.17 Impact Factor
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ABSTRACT: The spectral properties of metal-dielectric and metal-semiconductor 1D photonic crystals (PCs) are theoretically investigated, considering spatial dispersion in the metal and in the semiconductor, respectively. In the case of 1D PCs, composed of alternating metallic and dielectric slabs, we apply the classical fonnalism of the Boltzmann's kinetic equation for the distribution function of the conduction electrons in order to determine the nonlocal constitutive equation for the metallic slabs. Afterwards, we calculate the dispersion relation for the bulk modes in the 1D PC and compare it with that obtained within the Drude-Lorentz model, which is implicitly local. Another kind of nonlocal effects are studied by considering a metal-semiconductor 1D PC. In this case, the frequency-dependent dielectric function of the metallic component is described by the local Drude-Lorentz model, whereas for the semiconductor we use a Hopfield-Thomas dielectric function, which describes its nonlocal behavior near exciton resonance. The polariton dispersion curves for s-polarized modes in the metal-semiconductor photonic crystal are compared with those for a metal-dielectric PC. Because of the coupling of light with excitons, which undergo size quantization inside the thin semiconductor slabs, many photonic small bands appear. We study the changes in the photonic dispersion curves for the resonant 1D PC as the filling fraction of the metal is varied.
Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves and Workshop on Terahertz Technologies, 2007. MSMW '07. The Sixth International Kharkov Symposium on; 07/2007
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ABSTRACT: The coupling of magnetoexcitons in near-surface double quantum wells with the incident light is investigated theoretically. Making use of the Stahl's real-space density-matrix approach, we have calculated reflectivity and absorption spectra for double quantum wells. Our results show the effect of the exciton–surface interaction on the resonance structure in optical spectra for near-surface double quantum wells under the action of a strong magnetic field parallel to the growth direction. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
physica status solidi (c) 07/2004; 1(S1):S38 - S41.
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ABSTRACT: The optical response of near-surface localized excitons and their corresponding quantized longitudinal polarization waves in thin semiconductor films on substrate is investigated theoretically. The identification of resonances associated with such longitudinal modes in simple spectra of reflectivity for p-polarized incident light (Rp) is rather difficult because of the large damping factor for a thin film near the longitudinal frequency (ωL) and a background contribution to Rp. However, as is shown here, the quantized longitudinal polarization waves manifest themselves more clearly in spectra of 45° reflectometry, which is based upon the measurement of the difference between the reflectivity Rp and the squared reflectivity for s-polarized light (Rs2) with an angle of incidence of 45°. © 2003 American Institute of Physics.
Journal of Applied Physics 03/2003; 93(6):3308-3314. · 2.17 Impact Factor
