51,443 research outputs found
Wave Enhancement Through Optimization of Boundary Conditions
In this paper, we present a new and efficient approach for optimizing the transmission signal between two points in a cavity at a given frequency, by changing boundary conditions. The proposed approach makes use of recent results on the monotonicity of the eigenvalues of the mixed boundary value problem and on the sensitivity of Green's function to small changes in the boundary conditions. The switching of the boundary condition from Dirichlet to Neumann can be performed through the use of the recently modeled concept of metasurfaces which are comprised of coupled pairs of Helmholtz resonators. A variety of numerical experiments are presented to show the applicability and the accuracy of the proposed new methodology
Wave Enhancement Through Optimization of Boundary Conditions
In this paper, we present a new and efficient approach for optimizing the transmission signal between two points in a cavity at a given frequency, by changing boundary conditions. The proposed approach makes use of recent results on the monotonicity of the eigenvalues of the mixed boundary value problem and on the sensitivity of Green's function to small changes in the boundary conditions. The switching of the boundary condition from Dirichlet to Neumann can be performed through the use of the recently modeled concept of metasurfaces which are comprised of coupled pairs of Helmholtz resonators. A variety of numerical experiments are presented to show the applicability and the accuracy of the proposed new methodology
Optimal light harvesting structures at optical and infrared frequencies
One-dimensional light harvesting structures with a realistic geometry
nano-patterned on an opaque metallic film are optimized to render high
transmission efficiencies at optical and infrared frequencies. Simple design
rules are developed for the particular case of a slit-groove array with a given
number of grooves that are symmetrically distributed with respect to a central
slit. These rules take advantage of the hybridization of Fabry-Perot modes in
the slit and surface modes of the corrugated metal surface. Same design rules
apply for optical and infrared frequencies. The parameter space of the groove
array is also examined with a conjugate gradient optimization algorithm that
used as a seed the geometries optimized following physical intuition. Both
uniform and nonuniform groove arrays are considered. The largest transmission
enhancement, with respect to a uniform array, is obtained for a chirped groove
profile. Such enhancement is a function of the wavelength. It decreases from
39% in the optical part of the spectrum to 15% at the long wavelength infrared.Comment: 13 pages, 5 figure
Multilayer nanoparticle arrays for broad spectrum absorption enhancement in thin film solar cells
In this paper, we present a theoretical study on the absorption efficiency
enhancement of a thin film amorphous Silicon (a-Si) photovoltaic cell over a
broad spectrum of wavelengths using multiple nanoparticle arrays. The light
absorption efficiency is enhanced in the lower wavelengths by a nanoparticle
array on the surface and in the higher wavelengths by another nanoparticle
array embedded in the active region. The efficiency at intermediate wavelengths
is enhanced by the simultaneous resonance from both nanoparticle layers. We
optimize this design by tuning the radius of particles in both arrays, the
period of the array and the distance between the two arrays. The optimization
results in a total quantum efficiency of 62.35% for a 300nm thick a-Si
substrate.Comment: - Article Published in Optics Express on 7 Apr 2014. Link:
http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-103-A80
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