741 research outputs found
Adaptive Finite Element Method for Simulation of Optical Nano Structures
We discuss realization, properties and performance of the adaptive finite
element approach to the design of nano-photonic components. Central issues are
the construction of vectorial finite elements and the embedding of bounded
components into the unbounded and possibly heterogeneous exterior. We apply the
finite element method to the optimization of the design of a hollow core
photonic crystal fiber. Thereby we look at the convergence of the method and
discuss automatic and adaptive grid refinement and the performance of higher
order elements
Reduced basis method for computational lithography
A bottleneck for computational lithography and optical metrology are long
computational times for near field simulations. For design, optimization, and
inverse scatterometry usually the same basic layout has to be simulated
multiple times for different values of geometrical parameters. The reduced
basis method allows to split up the solution process of a parameterized model
into an expensive offline and a cheap online part. After constructing the
reduced basis offline, the reduced model can be solved online very fast in the
order of seconds or below. Error estimators assure the reliability of the
reduced basis solution and are used for self adaptive construction of the
reduced system. We explain the idea of reduced basis and use the finite element
solver JCMsuite constructing the reduced basis system. We present a 3D
optimization application from optical proximity correction (OPC).Comment: BACUS Photomask Technology 200
Rigorous Simulations of 3D Patterns on Extreme Ultraviolet Lithography Masks
Simulations of light scattering off an extreme ultraviolet lithography mask
with a 2D-periodic absorber pattern are presented. In a detailed convergence
study it is shown that accurate results can be attained for relatively large 3D
computational domains and in the presence of sidewall-angles and
corner-roundings.Comment: SPIE Europe Optical Metrology, Conference Proceeding
Analytical modeling and 3D finite element simulation of line edge roughness in scatterometry
The influence of edge roughness in angle resolved scatterometry at
periodically structured surfaces is investigated. A good description of the
radiation interaction with structured surfaces is crucial for the understanding
of optical imaging processes like, e.g. in photolithography. We compared an
analytical 2D model and a numerical 3D simulation with respect to the
characterization of 2D diffraction of a line grating involving structure
roughness. The results show a remarkably high agreement. The diffraction
intensities of a rough structure can therefore be estimated using the numerical
simulation result of an undisturbed structure and an analytically derived
correction function. This work allows to improve scatterometric results for the
case of practically relevant 2D structures
Projection crystallography
The birefringent properties of many crystalline substances can create vivid collages when combined with polarized illumination. High magnification photographs of these patterns can be produced simply without the use of a microscope or other expensive equipment. The technique involves projecting an enlarged crystal pattern with a condenser enlarger onto 35mm film
FEM investigation of leaky modes in hollow core photonic crystal fibers
Hollow-core holey fibers are promising candidates for low-loss guidance of
light in various applications, e.g., for the use in laser guide star adaptive
optics systems in optical astronomy. We present an accurate and fast method for
the computation of light modes in arbitrarily shaped waveguides. Maxwell's
equations are discretized using vectorial finite elements (FEM). We discuss how
we utilize concepts like adaptive grid refinement, higher-order finite
elements, and transparent boundary conditions for the computation of leaky
modes in photonic crystal fibers. Further, we investigate the convergence
behavior of our methods. We employ our FEM solver to design hollow-core
photonic crystal fibers (HCPCF) whose cores are formed from 19 omitted cladding
unit cells. We optimize the fiber geometry for minimal attenuation using
multidimensional optimization taking into account radiation loss (leaky modes).Comment: 8 page
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