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In this paper the response of light propagation in hypercrystals (I.E, structures composed by metamaterial) have been numerically analyzed. The heterojunctions were considered to demonstrate that the optical properties change the behavior of the structure at visible and optical frequencies. The structure is composed by periodic layers to combine properties of photonic crystals and hyperbolic metamaterials that present different physical properties not found in nature. In most of cases have been composed by metal and semiconductor in alternate layers. To design a structure the Fibonacci's sequence was used to define the sequence order of layers. The materials used in simulations are Gold and Aluminum for as metals and Silicon for the as semiconductor. To compose a heterojunction photo detector part it was considered the low work-function metal Aluminum, for the intrinsic crystal Silicon, and high work-function metal Gold in this sequential layers.

In this paper the response of electromagnetic waves propagation in plasmonic structures composed by metals and dielectrics has been numerically analyzed. Thermal-optical coefficient was considered to demonstrate that the optical properties change the behavior of the structure at visible and infrared frequencies. The structure is composed by alternated thin layers of metal and semiconductor. The materials used in simulations are Silver for metal, Silica and Silicon for the semiconductors. Under temperature variations, these materials change their properties, like refractive index and can affect optical properties like absorbance, transmittance and reflectance. Besides, the incident angle was considerate as a variable. The Finite Element Method has been used to carry the simulations.

The transmittance, reflectance and absorption of silver nanowires metamaterial embedded into a semiconductor matrix with optical gain are numerically investigated. Metamaterials may suffer from appreciable dissipative losses which are inherent for all plasmonic structures. The losses can significantly be reduced by introducing optical gain in the dielectric matrix by placing atomic or molecular impurities which are pumped by an external light source to create a population inversion. We numerically analyzed the optical properties when the semiconductor host material represents a gain medium. We calculate the transmittance, reflectance and absorption at normal incidence in the visible and near infrared ranges. We observed a peculiar behavior of their optical coefficients that can be explained by observing the field redistribution on the metamaterial.

The transmittance, reflectance and absorption of a nanowire metamaterial with optical gain are numerically simulated and investigated. It is assumed that the metamaterial is represented by aligned silver nanowires embedded into a semiconductor matrix, made of either silicon or gallium phosphide. The gain in the matrix is modeled by adding a negative imaginary part to the dielectric function of the semiconductor. It is found that the optical coefficients of the metamaterial depend on the gain magnitude in a non-trivial way: they can both increase and decrease with gain depending on the lattice constant of the metamaterial. This peculiar behavior is explained by the field redistribution between the lossy metal nanowires and the amplifying matrix material. These findings are significant for a proper design of nanowire metamaterials with low optical losses for diverse applications.

The absorption and reflection characteristics of multilayered nanoplasmonic gratings with sub wavelength sizes are analyzed in details by using an efficient finite element method. The multilayered structures are composed by several layers of nanoparticles of metals such as Silver, Gold and Aluminum embedded in dielectric such as amorphous silicon over a metallic substrate. The propagations characteristics for several geometrical configurations are obtained and a broadband reflection or absorption covering the near infrared wavelengths has been observed. The proposed nanoplasmonic structures have a great potential for applications in photovoltaic cells or polarizers by improving their reflection or absorption efficiency. Peaks of reflection or absorption larger than 80% were obtained and their performance over the near infrared can be improved by adequately tuning their geometrical parameters, the refractive index and thickness of the layers as well as the nanoparticles shape and size.

Broadband nanostructured metallic-dielectric absorbers and reflectors are of great interest in integrated optics and they have a great potential for applications like polarizers or reflectors for nanoantennas applications operating in optical frequencies, covering the interval of the O-E-S-C-L-U bands. In this work, novel geometric and optical configurations are numerically analyzed. The absorber or reflected central frequencies of the analyzed devices can be easily tuned over the entire communications wavelength band by varying their geometrics and optical parameters Peaks of absorption larger than 80% were obtained in optical wavelengths by using metals like silver and gold in combination with silica substrates.

Supercells composed of apodized subwavelength gratings are analyzed by an efficient frequency domain finite element method. The effects of the apodization on the broadband operation of the grating has been demonstrated.

We propose a strategy to design broadband absorbers. It is based on the apodization of a supercell composed of an array of subwavelength metallic-insulator gratings. The proposed absorber consists of grooves with variable depths in a metallic substrate filled with a dielectric material. It was demonstrated that the apodization procedure plays an important role in the required broadband operation of the proposed absorbers. The proposed absorber presented averaged values of absorption of the order of 94% for wavelengths from 700 to 2300 nm. The spectral response of the absorption coefficient, for a plane wave under normal incidence, has been calculated by using an efficient frequency-domain finite-element method.