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Berlin, Germany

Kato A.,Ruhr West University of Applied Sciences | Burger S.,Zuse Institute Berlin | Burger S.,JCMwave GmbH | Scholze F.,Physikalisch - Technische Bundesanstalt
Applied Optics

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 such as, e.g., in photolithography. We compared an analytical two-dimensional (2D) model and a numerical three-dimensional 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. © 2012 Optical Society of America. Source

Hiremath K.R.,Computational Nanooptics Group | Zschiedrich L.,JCMwave GmbH | Schmidt F.,Computational Nanooptics Group
Journal of Computational Physics

Nonlocal material response distinctively changes the optical properties of nano-plasmonic scatterers and waveguides. It is described by the nonlocal hydrodynamic Drude model, which - in frequency domain - is given by a coupled system of equations for the electric field and an additional polarization current of the electron gas modeled analogous to a hydrodynamic flow. Recent attempt to simulate such nonlocal model using the finite difference time domain method encountered difficulties in dealing with the grad-div operator appearing in the governing equation of the hydrodynamic current. Therefore, in these studies the model has been simplified with the curl-free hydrodynamic current approximation; but this causes spurious resonances. In this paper we present a rigorous weak formulation in the Sobolev spaces . H(curl) for the electric field and . H(div) for the hydrodynamic current, which directly leads to a consistent discretization based on Nédélec's finite element spaces. Comparisons with the Mie theory results agree well. We also demonstrate the capability of the method to handle any arbitrary shaped scatterer. © 2012 Elsevier Inc. Source

Zschiedrich L.,JCMwave GmbH | Blome T.,Zuse Institute Berlin | Greiner H.J.,Philips
Proceedings of SPIE - The International Society for Optical Engineering

We present novel numerical techniques for the simulation of the light outcoupling from state of the art organic light-emitting diodes (OLED). For the spatial discretization we use the finite element method which we apply in the frequency domain. To account for the large horizontal extension of the OLED we apply a recently proposed approach based on the Floquet transform which allows to restrict the calculations to the unit cell of a (quasi) periodic structure. Optically thick layers are efficiently treated by a plane wave expansion which we combine with the Finite Element Method by the domain decomposition method. We benchmark the new simulation tools for highly efficient state of the art OLED light extraction structures. © 2014 Copyright SPIE. Source

Soltwisch V.,Physikalisch - Technische Bundesanstalt | Burger S.,Zuse Institute Berlin | Burger S.,JCMwave GmbH | Scholze F.,Physikalisch - Technische Bundesanstalt
Proceedings of SPIE - The International Society for Optical Engineering

Extreme W scatterometry using radiation in the extreme ultraviolet photon energy range, with wavelengths around 13.5 nm, provides direct information on the performance of EUV optical components, e.g. EUV phoÂ? tomasks, in their working wavelength regime. Scatterometry with horizontal diffraction geometry, parallel to the grating lines (conical), and vertical scattering geometry, perpendicular to the lines (in-plane), was performed on EUV lithography mask test structures. Numerical FEM based simulations, using a rigorous Maxwell solver, compare both experimental set-ups with focus on the sensitivity of the diffraction intensities particularly with respect to the side wall angle. © 2013 SPIE. Source

Hansen P.-E.,Danish Fundamental Metrology | Burger S.,JCMwave GmbH | Burger S.,Zuse Institute Berlin
Proceedings of SPIE - The International Society for Optical Engineering

Hollow-core photonic bandgap fibers guide light using diffraction rather than total internal reflection as is the case with normal single- mode communications fibers. The fibers consist of a hollow capillary (~19 micrometers in diameter) surrounded by capillary (~4 micrometers in diameter) arranged in a honey-comb like structure. The honey-comb structure scatters light in the core such that light within the bandgap wavelengths cannot escape from the core. However, the bandgap properties greatly depend on the accuracy with which the microstructures can be controlled during the fabrication process. For measuring the geometrical properties of hollow core photonic crystal fibers with a honeycomb cladding structure we use an angular scatterometric setup. For analyzing the experimentally obtained data we rigorously compute the scattering signal by solving Maxwell's equations with finite-element methods. This contribution focuses on the numerical analysis of the problem. A convergence analysis demonstrates that we reach highly accurate solutions. Our results show very good qualitative agreement between experimental and numerical results. We furthermore demonstrate concepts for accurately monitoring dimensional parameters in the fiber manufacturing process. © 2013 SPIE. Source

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