Absorption effects on plasmon polariton-gap solitons in Kerr/metamaterial superlattices

ABSTRACT: A thorough study of the absorption effects on the plasmon polariton-gap solitoninduced transparency in 1D Kerr/metamaterial superlattices is presented. Results indicate that for frequencies close to the bottom or top edge of the bulk-like longitudinal plasmon-polariton gap, the transmission of a finite Kerr/metamaterial superlattice presents a multistable behavior, switching from very low values to the maximum transparency at particular values of the incident power even in the presence of loss effects. Moreover, calculations suggest the existence of resonant plasmon polariton-gap solitons of various orders depending on the particular value of the incident power. The present results reveal that plasmon polariton-gap soliton-induced resonant solutions lead to the transparency of a stack with nonlinear inclusions, a nonlinear optical analog of the electronic barrier-transmission resonances

Intraband absorption in GaAs-(Ga,Al)As variably spaced semiconductor superlattices under crossed electric and magnetic fields

ABSTRACT: A theoretical study of the intraband absorption properties of GaAs-Ga1−xAlxAs variably spaced semiconductor superlattices under crossed magnetic and electric fields is presented. Calculations are performed for the applied electric field along the growth-axis direction, whereas the magnetic field is considered parallel to the heterostructure layers. By defining a critical electric field so that the heterostructure energy levels are aligned in the absence of the applied magnetic fields, one finds that, in the weak magnetic-field regime, an abrupt red shift of the absorption coefficient maxima is obtained at fields equal to or larger than the critical electric field, a fact which may be explained from the localization properties of the electron wave functions. Results in the strong magnetic-field regime reveal a rich structure on the intraband absorption coefficient which may be explained from the strong dispersion exhibited by both the energy levels and transition strengths as functions of the generalized orbit-center position. Moreover, the possibility of occurrence of absorption in a wide frequency range is also demonstrated. Present calculated results may be of interest for future design and improvement of multilayered-based photovoltaic and solar-cell devices

Localización anómala de la luz en superredes fotónicas unidimensionales desordenadas

ABSTRACT: The Anderson localization of light in one-dimensional disordered photonic superlattices is theoretically studied. The system is considered to be made of alternating dispersive and nondispersive layers of different randomthickness. Dispersive slabs of the heterostructure are characterized by Drude-like frequency-dependent electric permittivities and magnetic permeabilities. Numerical results for the localization length are obtained via an analytical model, only valid in the case of weak disorder, and also through its general definition involving the transmissivity of the multilayered system. Anomalous lambda4- and lamnda-4 dependencies of the localization length in positive-negative disordered photonic superlattices are obtained, in certain cases, in the long and short wavelength limits, respectively.RESUMEN: La localización de Anderson de la luz en superredes fotónicas desordenadas unidimensionales es estudiada teóricamente. El sistema se considera compuesto de capas alternadas dispersivas y no dispersivas de diferentes espesores aleatorios. Las capas dispersivas de la heteroestructura están caracterizadas por permitividades eléctricas y permeabilidades magnéticas tipo Drude dependientes de la frecuencia. Los resultados numéricos para la longitud de la localización son obtenidos mediante un modelo analítico, solo válido en caso de desorden débil, y también a través de la definición general que involucra la transmisividad del sistema multicapas. Las dependencias anómalas lambda4 y lambda-4 de la longitud de localización en superredes fotónicas desordenadas son obtenidas, en ciertos casos, en los límites de longitudes de onda larga y corta, respectivamente

Band edge states of the (n)=0 gap of Fibonacci photonic lattices

ABSTRACT: The stationary and normally incident electromagnetic modes in Fibonacci lattices with generating layers of positive and negative indices of refraction are calculated by a transfer-matrix technique. It is shown that the condition for constructive interference of reflected waves is fulfilled when the ratio of optical paths in positive and negative media are given by the golden ratio. Furthermore, in the long-wavelength limit, it is demonstrated that the edges of the (n)=0 gap are the frequencies satisfying the conditions (E)=0 and (u)=0

Plasmon polariton and (n)= 0 non-Bragg gaps in superlattices with metamaterials

ABSTRACT: We consider one-dimensional photonic superlattices made up of alternate layers of a right-handed nondispersive material and a metamaterial with Drude-type dielectric permittivity and magnetic permeability. By thoroughly investigating the dispersion relation for the propagation of obliquely incident optical fields obtained from Maxwell’s equations and the transfer-matrix technique, we demonstrate that, in the long-wavelength limit, the dispersion is the same that one would obtain by considering a homogeneous effective medium with Drude-type responses at shifted electric and magnetic plasmon frequencies. Moreover, we show that the plasmon polariton and (n)= 0 non-Bragg gaps correspond to regions of the low-energy spectrum where the effective medium is absorptive, exhibiting an imaginary effective refraction index

Metric-signature topological transitions in dispersive metamaterials

ABSTRACT: The metric signature topological transitions associated with the propagation of electromagnetic waves in a dispersive metamaterial with frequency-dependent and anisotropic dielectric and magnetic responses are examined in the present work. The components of the reciprocal-space metric tensor depend upon both the electric permittivity and magnetic permeability of the metamaterial, which are taken as Drude-like dispersive models. A thorough study of the frequency dependence of the metric tensor is presented which leads to the possibility of topological transitions of the isofrequency surface determining the wave dynamics inside the medium, to a diverging photonic density of states at some range of frequencies, and to the existence of large wave vectors’ modes propagating through the metamaterial

Plasmon polaritons in 1D Cantor-like fractal photonic superlattices containing a left-handed material

ABSTRACT: The propagation of light incident upon a 1D photonic superlattice consisting of successive stacking of alternate layers of a right-handed nondispersive material and a metamaterial, arranged to form a Cantor-like fractal, is considered. Plasmon-polariton excitations are thoroughly investigated within the transfer-matrix approach and shown to strongly depend on the Cantor step number N. More specifically, the number of plasmon-polariton bands corresponds to the number 2N −1 of metamaterial layers within the unit cell

Plasmon polaritons in photonic metamaterial superlattices : absorption effects

ABSTRACT: We discuss the propagation of electromagnetic waves in layered structures made up of alternate layers of air and metamaterials. The role played by absorption on the existence of electric and magnetic plasmon polaritons is investigated. Results show that plasmon-polariton modes are robust even in the presence of rather large absorption

Plasmon polaritons in photonic metamaterial Fibonacci superlattices

ABSTRACT: We study the properties of plasmon polaritons in one-dimensional photonic metamaterial superlattices resulting from the periodic repetition of a Fibonacci structure. We assume the system made up of positive refraction and metamaterial layers. A Drude-type dispersive response for both the dielectric permittivity and magnetic permeability of the left-handed material is considered. Maxwell’s equations are solved for oblique incidence by using the transfer-matrix formalism. Our results show that the plasmon-polariton modes are considerably affected by the increasing of the Fibonacci-sequence order of the elementary cell. The loss of the long-range spatial coherence of the electromagnetic field along the growth direction, which is due to the quasiperiodicity of the elementary cell, leads to the splitting of the plasmon-polariton frequencies, resulting in a Cantor-type frequency spectra. Moreover, the calculated photonic dispersion indicates that if the plasma frequency is chosen within the photonic (n(w))=0 gap then the plasmon-polariton modes behave essentially as pure plasmon modes

Unfolding of plasmon-polariton modes in one-dimensional layered systems containing anisotropic left-handed materials

The propagation of electromagnetic waves through a 1-dimensional layered system containing alternate layers of air and a uniaxial, anisotropic, left-handed material is investigated. The optical axis of this material is along the stacking direction and the components of the electric permittivity and magnetic permeability tensors that characterize the metamaterial are described by Drude-type responses. Different plasmon frequencies are considered for directions parallel and perpendicular to the optical axis. As in the isotropic case, plasmon polariton modes are found in the neighborhood of the plasmon frequency corresponding to the optical axis. Moreover, it is shown that, depending on the relation between the two plasmon frequencies of the metamaterial, anisotropy leads to the unfolding of an infinite number of nearly dispersionless plasmon-polariton bands either above or below the parallel plasmon frequency