Publications (17)29.42 Total impact
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ABSTRACT: Nowadays photonic crystals are widely used in many different applications. One of the most used methods to compute their band structure is the plane wave method (PWM). However, it can only be applied directly to nondispersive media and be extended to systems with a few model dielectric functions. We explore an extension of the PWM to photonic crystals containing dispersive materials, that solves an eigenvalue equation for the Bloch wave vectors. First we compare our calculation with analytical results for one dimensional photonic crystals containing Si using experimental values of its optical parameters, and obtainig very well agreement, even for the spectrum region with strong absorption. Then, using the same method, we computed the band structure for a two dimensional photonic crystal without absorption, formed by an square array of MgO cylinders in air. The optical parameters for MgO were modeled with the Lorentz dielectric function. Finally, we studied an array of MgO cylinders in a metal, using Drude model without absorption, for the metal dielectric function. For this last case, we study the gapmidgap ratio as a function of the filling fraction for both the square and triangular lattice. The gapmidgap ratio is larger for the triangular lattice, with a maximum value of 10% for a filling fraction of 0.6. Our results show that the method can be applied to dispersive materials, and then to a wide range of applications where photonic crystals can be used.  [Show abstract] [Hide abstract]
ABSTRACT: The THz and infrared photonic dispersion relations of superlattices composed of polaritonic material and bismuth (Bi) layers are theoretically investigated. The semimetal Bi presents a farinfrared response described by a Drudelike formula with a large highfrequency background dielectric constant. We have considered three different polaritonic materials: NaBr, LiCl and LiH, such that the Bi plasma frequency lies above, inbetween and below the characteristic frequencies of the polaritonic materials, respectively. Investigating the photonic band structure of each superlattice, we have found that when the Bi plasma frequency lies below the polaritonic gap, appears a photonic pass band of negative dispersion for TM modes just above the longitudinaloptical phonon frequency, attributed to the frequency dependence of the permittivity for the polaritonic material and the large highfrequency background dielectric constant for Bi, that can be relevant to the metamaterials community. (C) 2015 Optical Society of America  [Show abstract] [Hide abstract]
ABSTRACT: We discuss the propagation of electromagnetic waves through a onedimensional periodic array of bilayers with metal inclusions. We show that the nonlocality of metal conductivity leads to the emergence of the fundamental collisionless Landau damping. It cannot be neglected, not only when prevailing over ordinary collision damping, but even when these two kinds of electromagnetic absorption are of the same order. Landau damping always exists and considerably alters the photonic transmission of the array within the THz and nearinfrared frequency range.  [Show abstract] [Hide abstract]
ABSTRACT: On the basis of the formalism of the Boltzmann kinetic equation for the distribution function of the conduction electrons, the photonic band structure of binary dielectricmetal superlattice is theoretically studied. Using the constitutive nonlocal relation between the electrical current density and the electric field inside the metallic layer, the dispersion equation for photonic eigenmodes in the periodic stack is analytically expressed in terms of the surface impedances at the interfaces of the metal and dielectric layers. In the case of very thin metallic layers, the optic spectrum for the superlattice exhibits narrow pass bands as a result of the strong contrast between the impedances of the dielectric and the metal. The narrow pass bands are attributed to FabryPerot resonances in the relativelythick dielectric layer. The metal nonlocality is well pronounced in the infrared and, therefore, the nonlocal effect upon the photonic band structure of the superlattice can be strong when the FabryPerot resonance bands are in that frequency range. Our results for the photonic spectrum have been compared with those obtained within the local DrudeLorentz model. Noticeably differences not only in the the magnitude, but also in the sign of the real part of the Bloch wave number in the FabryPerot resonance bands, have been found.  [Show abstract] [Hide abstract]
ABSTRACT: We theoretically investigate the optical properties of onedimensional photonic crystals composed of two alternating layers, namely a semiconductor film and a metallic one. The nonlocal optical response of the semiconductor is here described by using a resonant excitonic dielectric function, whereas the local response function of the metal film is modeled with Drude formula. We calculate optical spectra of the metal–semiconductor 1D photonic crystal for both s and ppolarization geometries. In both cases the spectra exhibit a rich resonance structure due to the coupling of sizequantized excitons inside the semiconductor film with light. We show the difference between s and ppolarization reflectivity as the angle of incidence is increased. In the ppolarization geometry, besides transverse excitonpolariton modes, longitudinal polarization waves are excited producing additional spectral resonances. The spectra become radically different when the frequency corresponding to the minimum of the first photonic passband is close to the exciton resonance, since such a frequency is distinct for s and ppolarized modes. We also show how reflectivity spectra for both polarizations are modified with varying the metal filling fraction which controls the width of the gap below the lowest frequency band.  [Show abstract] [Hide abstract]
ABSTRACT: We theoretically investigate the coupling of light with magnetoexcitons in nearsurface 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 realspace densitymatrix approach. In particular, we have solved the system of equations for the coherentwave amplitude and the electromagnetic fields for InGaAs/GaAs quantumwell 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.  [Show abstract] [Hide abstract]
ABSTRACT: We have derived simple analytical expressions for the frequencydependent effective permittivity tensor of a onedimensional metaldielectric photonic crystal in the long wavelength limit. Our results describe the transition between the regime, described by Rytov's formulas for sufficiently long waves, and that predicted by Xu et al. [6], where the effective plasma frequency is independent of the metalliclayer parameters. The derived expressions can be useful for determining the frequency intervals where such an anisotropic system can exhibit metamaterial behavior.  [Show abstract] [Hide abstract]
ABSTRACT: Exact analytic formulas for calculating the effective permittivity, permeability, and crossed magnetoelectric tensors for photonic crystals in the longwavelength 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 threedimensional 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.  [Show abstract] [Hide abstract]
ABSTRACT: We investigate theoretically the coupling of exciton with light in a onedimensional photonic crystal. The unit cell of the crystal consists of two alternating layers, namely a metallic layer and a semiconductor one. The frequencydependent 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 spolarized modes in the metalsemiconductor photonic crystal is compared with that for a dielectricsemiconductor photonic crystal. Because of the metal layers, a lowfrequency gap appears in the photonic band structure. The presence of the semiconductor gives rise to photonic bands associated with the coupling of light with sizequantized excitón states. At frequencies above the longitudinal exciton frequency, the photonic band structure exhibits anticrossing phenomena produced by the upper excitonpolariton mode and sizequantized excitons. It is found that the anticrossing phenomena in the metalsemiconductor photonic crystal occur at higher frequencies in comparison with the dielectricsemiconductor case.  [Show abstract] [Hide abstract]
ABSTRACT: The optical properties of exciton polaritons in onedimensional photonic crystals are theoretically investigated. The periodic photonic struc ture is formed by two alternating layers, namely a local dielectric layer and a thin semiconductor one which is characterized by a nonlocal excitonic dielectric function. We calculate reflectivity spectra for onedimensional MgOCuCl photonic crystals, which exhibit a rich res onance structure because of the optical manifestation of sizequantized excitons. We study the changes in the resonance structure as the thickness of the thin semiconductor layer is varied. It is found that odd quantizedexciton modes are well manifest in the optical spectra in comparison with even states. We have also investigated the effect of both homogeneous bulk damping and interfaceinduced broadening upon the reflectivity resonances. The broadening due to interface disorder is calculated with the selfconsistent Green's function method. 
Article: Magnetoexcitons in nearsurface symmetric and asymmetric double quantum wells: Optical properties
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ABSTRACT: We present a theoretical study of the optical properties of excitons in symmetric and asymmetric bulk and nearsurface 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 realspace densitymatrix 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 surfacemagnetoexciton interaction upon the reflectivity and absorption for nearsurface 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. 
Conference Paper: SpatialDispersion Effects in OneDimensional Photonic Crystals with Metallic Inclusions
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ABSTRACT: The spectral properties of metaldielectric and metalsemiconductor 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 DrudeLorentz model, which is implicitly local. Another kind of nonlocal effects are studied by considering a metalsemiconductor 1D PC. In this case, the frequencydependent dielectric function of the metallic component is described by the local DrudeLorentz model, whereas for the semiconductor we use a HopfieldThomas dielectric function, which describes its nonlocal behavior near exciton resonance. The polariton dispersion curves for spolarized modes in the metalsemiconductor photonic crystal are compared with those for a metaldielectric 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.  [Show abstract] [Hide abstract]
ABSTRACT: The coupling of magnetoexcitons in nearsurface double quantum wells with the incident light is investigated theoretically. Making use of the Stahl's realspace densitymatrix 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 nearsurface double quantum wells under the action of a strong magnetic field parallel to the growth direction. (© 2004 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim)  [Show abstract] [Hide abstract]
ABSTRACT: The optical response of excitons in quantum wells, close to the sample boundary and under the action of a strong magnetic field perpendicular to their plane, is investigated theoretically. Solving the system of coupled equations for the coherent electronhole interband amplitude and the electromagnetic field, reflectivity spectra for such nanostructures are calculated. The effect of the interaction of magnetoexcitons with the sample surface on the resonance structure of reflectivity spectra is analyzed. These optical spectra are also affected by the phase change of the electromagnetic wave as it propagates in the cap layer, overlying the quantum well. 
Article: Optical manifestation of quantized longitudinal polarization waves of excitons in thin films
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ABSTRACT: The optical response of nearsurface 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 ppolarized 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 spolarized light (Rs2) with an angle of incidence of 45°. © 2003 American Institute of Physics.  [Show abstract] [Hide abstract]
ABSTRACT: It is well known that a semiinfinite medium that is nonmagnetic and homogeneous admits surface polaritons with TM (p)polarization, while TE (s)polarized surface modes do not exist. It was pointed out that spolarized surface phonon polaritons could be guided by a suitable transition layer^1, however such waves have not been detected.Our calculations show that certain treated CdS and CdSe surfaces^2 can guide surface exciton polaritons that are spolarized. This conclusion is supported by dispersion relations, field profiles, and Attenuated Total Reflectivity spectra. 1. V. E. Kravtsov et al., Solid State Comm. 50, 741 (1984). 2. V. A. Kiselev et al., Sov. Phys. Solid State 28, 1655 (1986); A. S. Batyrev et al., JETP Lett. 62, 408 (1995). This research was partially financed by CONACyT.  [Show abstract] [Hide abstract]
ABSTRACT: The influence of the surfacepotential shape on exciton optical spectra for thin semiconductor films is investigated theoretically. Using a realistic model with both intrinsic and extrinsic contributions, we calculate the polarization vector and the electric field in the case of spolarized incident light at one of the thinfilm surfaces. Our analytic results are employed to study the relation between the surface potential parameters and the spectra of reflectivity and transmissivity. The generation of nearsurface localized excitons and their optical manifestation are also analyzed.
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55  Citations  
29.42  Total Impact Points  
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Institutions

19942016

Meritorious Autonomous University of Puebla
 Facultad de Ciencias Físico Matemáticas
Ejido Puebla, Baja California, Mexico
