423 research outputs found
Partially-disordered photonic-crystal thin films for enhanced and robust photovoltaics
We present a general framework for the design of thin-film photovoltaics
based on a partially-disordered photonic crystal that has both enhanced
absorption for light trapping and reduced sensitivity to the angle and
polarization of incident radiation. The absorption characteristics of different
lattice structures are investigated as an initial periodic structure is
gradually perturbed. We find that an optimal amount of disorder controllably
introduced into a multi-lattice photonic crystal causes the characteristic
narrow-band, resonant peaks to be broadened resulting in a device with enhanced
and robust performance ideal for typical operating conditions of photovoltaic
applications.Comment: 5 pages, 4 figure
Can high fidelity human patient simulators help biomedical science students better understand complex concepts such as anticholinergic burden?
Peer reviewedPublisher PD
A novel boundary element method using surface conductive absorbers for full-wave analysis of 3-D nanophotonics
Fast surface integral equation (SIE) solvers seem to be ideal approaches for
simulating 3-D nanophotonic devices, as these devices generate fields both in
an interior channel and in the infinite exterior domain. However, many devices
of interest, such as optical couplers, have channels that can not be terminated
without generating reflections. Generating absorbers for these channels is a
new problem for SIE methods, as the methods were initially developed for
problems with finite surfaces. In this paper we show that the obvious approach
for eliminating reflections, making the channel mildly conductive outside the
domain of interest, is inaccurate. We describe a new method, in which the
absorber has a gradually increasing surface conductivity; such an absorber can
be easily incorporated in fast integral equation solvers. Numerical experiments
from a surface-conductivity modified FFT-accelerated PMCHW-based solver are
correlated with analytic results, demonstrating that this new method is orders
of magnitude more effective than a volume absorber, and that the smoothness of
the surface conductivity function determines the performance of the absorber.
In particular, we show that the magnitude of the transition reflection is
proportional to 1/L^(2d+2), where L is the absorber length and d is the order
of the differentiability of the surface conductivity function.Comment: 10 page
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