22 research outputs found
Photonic band-gap engineering for volume plasmon polaritons in multiscale multilayer hyperbolic metamaterials
We theoretically study the propagation of large-wavevector waves (volume
plasmon polaritons) in multilayer hyperbolic metamaterials with two levels of
structuring. We show that when the parameters of a subwavelength
metal-dielectric multilayer ("substructure") are modulated ("superstructured")
on a larger, wavelength scale, the propagation of volume plasmon polaritons in
the resulting multiscale hyperbolic metamaterials is subject to photonic band
gap phenomena. A great degree of control over such plasmons can be exerted by
varying the superstructure geometry. When this geometry is periodic, stop bands
due to Bragg reflection form within the volume plasmonic band. When a cavity
layer is introduced in an otherwise periodic superstructure, resonance peaks of
the Fabry-Perot nature are present within the stop bands. More complicated
superstructure geometries are also considered. For example, fractal Cantor-like
multiscale metamaterials are found to exhibit characteristic self-similar
spectral signatures in the volume plasmonic band. Multiscale hyperbolic
metamaterials are shown to be a promising platform for large-wavevector bulk
plasmonic waves, whether they are considered for use as a new kind of
information carrier or for far-field subwavelength imaging.Comment: 12 pages, 10 figures, now includes Appendix
Thermal emission control via bandgap engineering in aperiodically designed nanophotonic devices
Aperiodic photonic crystals can open up novel routes for more efficient photon management due to increased degrees of freedom in their design along with the unique properties brought about by the long-range aperiodic order as compared to their periodic counterparts. In this work we first describe the fundamental notions underlying the idea of thermal emission/absorption control on the basis of the systematic use of aperiodic multilayer designs in photonic quasicrystals. Then, we illustrate the potential applications of this approach in order to enhance the performance of daytime radiative coolers and solar thermoelectric energy generators
On the behavior of the Sierpinski multiband fractal antenna
The multiband behavior of the fractal Sierpinski antenna is described. Due to its mainly triangular shape, the antenna is compared to the well-known single-band bow-tie antenna. Both experimental and numerical results show that the self-similarity properties of the fractal shape are translated into its electromagnetic behavior. A deeper physical insight on such a behavior is achieved by means of the computed current densities over the antenna surface, which also display some similarity properties through the bands.Peer Reviewe
Spectral and polarization effects in deterministically nonperiodic multilayers containing optically anisotropic and gyrotropic materials
Influence of material anisotropy and gyrotropy on optical properties of
fractal multilayer nanostructures is theoretically investigated. Gyrotropy is
found to uniformly rotate the output polarization for bi-isotropic multilayers
of arbitrary geometrical structure without any changes in transmission spectra.
When introduced in a polarization splitter based on a birefringent fractal
multilayer, isotropic gyrotropy is found to resonantly alter output
polarizations without shifting of transmission peak frequencies. The design of
frequency-selective absorptionless polarizers for polarization-sensitive
integrated optics is outlined
A peculiarity of localized mode transfiguration of a Cantor-like chiral multilayer
A fractal-like (Cantor-like) stratified structure of chiral and convenient
isotropic layers is considered. Peculiarities of the wave localization,
self-similarity, scalability and sequential splitting in the reflected field of
both the co-polarized and cross-polarized components are studied. The appearing
of the additional peak multiplets in stopbands is revealed, and a correlation
of their properties with chirality parameter is established.Comment: 10 pages, 5 figure
Omnidirectional reflection from generalized Fibonacci quasicrystals
We determine the optimal thicknesses for which omnidirectional reflection from generalized Fibonacci quasicrystals occurs. By capitalizing on the idea of wavelength- and angle-averaged reflectance, we assess in a consistent way the performance of the different systems. Our results indicate that some of these aperiodic arrangements can largely over-perform the conventional photonic crystals as omnidirectional reflection is concerned
Spectral scalability and optical spectra of fractal multilayer structures: FDTD analysis
An investigation of the optical properties and band structures for the conventional and Fibonacci photonic crystals (PCs) based on SrTiO3 and Sb2Te3 is made in the present research. Here, we use one-dimensional SrTiO3- and Sb2Te3-based layers. We have theoretically calculated the photonic band structure and transmission spectra of SrTiO3- and Sb2Te3-based PC superlattices. The position of minima in the transmission spectrum correlates with the gaps obtained in the calculation. The intensity of the transmission depths is more intense in the case of higher refractive index contrast between the layers. © 2016, Springer-Verlag Berlin Heidelberg
Band gap and optical transmission in the Fibonacci type one-dimensional A5B6C7 based photonic crystals
In this work, we present an investigation of the optical properties and band structure calculations for the photonic crystal structures (PCs) based on one-dimensional (1D) photonic crystal. Here we use 1D A5B6C7(A:Sb; B:S,Se; C:I) based layers in air background. We have theoretically calculated photonic band structure and optical properties of A5B6C7(A:Sb; B:S,Se; C:I) based PCs. In our simulation, we employed the finite-difference time domain (FDTD) technique and the plane wave expansion method (PWE) which implies the solution of Maxwell equations with centered finite-difference expressions for the space and time derivatives. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim