TY - JOUR A1 - Gutsche, Philipp A1 - Poulikakos, Lisa A1 - Hammerschmidt, Martin A1 - Burger, Sven A1 - Schmidt, Frank T1 - Time-harmonic optical chirality in inhomogeneous space JF - Proc. SPIE Y1 - 2016 U6 - https://doi.org/10.1117/12.2209551 VL - 9756 SP - 97560X ER - TY - GEN A1 - Gutsche, Philipp A1 - Poulikakos, Lisa A1 - Burger, Sven A1 - Hammerschmidt, Martin A1 - Schmidt, Frank T1 - Optical chirality: conservation law in arbitrary space T2 - 606. WE-Heraeus-Seminar on Nanophotonics and Complex Spatial Modes of Light N2 - The introduction of the near-field quantity of optical chirality has emerged in various numerical and few experimental studies of local chirality enhancement due to its relation to the excitation rate of chiral molecules. This time-even pseudoscalar has been dismissed as being a higher-order version of helicity. Nevertheless, we revisit the derivation of the underlying conservation law and define optical chirality in media similar to. We identify the mechanism of chirality conversion by either inhomogeneous or anisotropic space to complement the conservation of optical chirality. The conservation law of optical chirality in arbitrary space enables the extension of the concept of polarization to the near-field where no distiniguished propagation direction of light is present. We show that the connection of electromagnetic energy and optical chirality provide the ability to define a circular polarization basis in time-harmonic near-field analysis. In order to illustrate our theory, we present electromagnetic field simulations of simple as well as more complex nanostructures. Results using the well-known far-field polarization concept are readily reproduced and extended from the point of view of chirality conversion. Y1 - 2016 ER - TY - JOUR A1 - Hammerschmidt, Martin A1 - Barth, Carlo A1 - Pomplun, Jan A1 - Burger, Sven A1 - Becker, Christiane A1 - Schmidt, Frank T1 - Reconstruction of photonic crystal geometries using a reduced basis method for nonlinear outputs JF - Proc. SPIE N2 - Maxwell solvers based on the hp-adaptive finite element method allow for accurate geometrical modeling and high numerical accuracy. These features are indispensable for the optimization of optical properties or reconstruction of parameters through inverse processes. High computational complexity prohibits the evaluation of the solution for many parameters. We present a reduced basis method (RBM) for the time-harmonic electromagnetic scattering problem allowing to compute solutions for a parameter configuration orders of magnitude faster. The RBM allows to evaluate linear and nonlinear outputs of interest like Fourier transform or the enhancement of the electromagnetic field in milliseconds. We apply the RBM to compute light-scattering off two dimensional photonic crystal structures made of silicon and reconstruct geometrical parameters. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-58187 VL - 9756 SP - 97561R ER - TY - JOUR A1 - Hammerschmidt, Martin A1 - Herrmann, Sven A1 - Pomplun, Jan A1 - Burger, Sven A1 - Schmidt, Frank T1 - Model order reduction for the time-harmonic Maxwell equation applied to complex nanostructures JF - Proc. SPIE N2 - Fields such as optical metrology and computational lithography require fast and efficient methods for solving the time-harmonic Maxwell's equation. Highly accurate geometrical modelling and numerical accuracy at low computational costs are a prerequisite for any simulation study of complex nano-structured photonic devices. We present a reduced basis method (RBM) for the time-harmonic electromagnetic scattering problem based on the hp-adaptive finite element solver JCMsuite capable of handling geometric and non-geometric parameter dependencies allowing for online evaluations in milliseconds. We apply the RBM to compute light-scattering at optical wavelengths of periodic arrays of fin field-effect transistors (FinFETs) where geometrical properties such as the width and height of the fin and gate can vary in a large range. Y1 - 2016 U6 - https://doi.org/10.1117/12.2212367 VL - 9742 SP - 97420M ER - TY - JOUR A1 - Hammerschmidt, Martin A1 - Herrmann, Sven A1 - Pomplun, Jan A1 - Burger, Sven A1 - Schmidt, Frank T1 - Reduced basis method for electromagnetic scattering problem: a case study for FinFETs JF - Optical and Quantum Electronics N2 - Optical 3D simulations in many-query and real-time contexts require new solution strategies. We study an adaptive, error controlled reduced basis method for solving parametrized time-harmonic optical scattering problems. Application fields are, among others, design and optimization problems of nano-optical devices as well as inverse problems for parameter reconstructions occurring e. g. in optical metrology. The reduced basis method pre- sented here relies on a finite element modeling of the scattering problem with parametrization of materials, geometries and sources. Y1 - 2016 U6 - https://doi.org/10.1007/s11082-016-0530-1 VL - 48 SP - 250 ER - TY - JOUR A1 - Jäger, Klaus A1 - Barth, Carlo A1 - Hammerschmidt, Martin A1 - Herrmann, Sven A1 - Burger, Sven A1 - Schmidt, Frank A1 - Becker, Christiane T1 - Simulations of sinusoidal nanotextures for coupling light into c-Si thin-film solar cells JF - Opt. Express Y1 - 2016 U6 - https://doi.org/10.1364/OE.24.00A569 VL - 24 SP - A569 ER - TY - THES A1 - Hammerschmidt, Martin T1 - Optical simulation of complex nanostructured solar cells with a reduced basis method N2 - Simulations of optical processes and complex nanostructured devices have become omnipresent in recent years in several fields of current research and industrial applications, not limited to the field of photovoltaics. Devices or processes are optimized with respect to a certain objective where the underlying physical processes are described by partial differential equations. In photovoltaics and photonics electromagnetic fields are investigated which are governed by Maxwell’s equations. In this thesis a reduced basis method for the solution of the parameter dependent electromagnetic scattering problem with arbitrary parameters is developed. The method is developed with the specific challenges arising in optical simulations of thin-film silicon solar cells in mind. These are large in domain size and have a complex three-dimensional structure, making optimization tasks infeasible if high-accuracy of the electromagnetic field solution is required. The application of the empirical interpolation methods allows to expand an arbitrary parameter dependence affinely. Thus not only geometries, but also material tensors and source fields can be parameterized. Additionally, the required non-linear post-processing steps of the electromagnetic field to derive energy fluxes or volume absorption are addressed. The reduced basis method allows to reduce the computational costs by orders of magnitude compared to efficient finite element solvers. In addition, an efficient tailored domain decomposition algorithm is presented to model incoherent layers or illuminations in optical systems efficiently. This is of particular interest for solar cells in superstrate configuration where the absorber is illuminated through a glass substrate. The developed methods are employed in application examples taken from collaborations with experimentalists active in the joint lab “BerOSE” (Berlin Joint Lab for Optical Simulations for Energy Research). The optical model of a thin-film silicon multi-junction with incoherent light-trapping is characterized in great detail. The computational gains through hybrid, hp adaptive finite elements are studied and the incoherent domain decomposition algorithm is applied to model a more realistic light-trapping by the glass substrate. The numerical examples of a hexagonal nano-hole array and multi-junction silicon solar cell with a tunable intermediate reflector layer show that the reduced basis method is well suited as a forward solver for modeling and optimization tasks arising in photovoltaics and photonics. Reduced models for illumination and geometric parameters are built providing up to five orders of magnitude savings in computational costs. Resonance phenomena present in the nano-hole array example are detected and the model adapts itself automatically. KW - reduced basis method; model reduction; electromagnetics; photonics; solar cells; nanooptics; Maxwells equations; incoherence Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:188-fudissthesis000000102429-1 UR - http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000102429 ER - TY - CHAP A1 - Jäger, Klaus A1 - Hammerschmidt, Martin A1 - Köppel, Grit A1 - Burger, Sven A1 - Becker, Christiane T1 - On Accurate Simulations of Thin-Film Solar Cells With a Thick Glass Superstrate T2 - Light, Energy and the Environment 2016 Y1 - 2016 U6 - https://doi.org/10.1364/PV.2016.PM3B.5 SP - PM3B.5 ER - TY - CHAP A1 - Jäger, Klaus A1 - Barth, Carlo A1 - Hammerschmidt, Martin A1 - Herrmann, Sven A1 - Burger, Sven A1 - Schmidt, Frank A1 - Becker, Christiane ED - European Society for Quantum Solar Energy Conversion, T1 - Sinusoidal Nanotextures for Enhanced Light Management in Thin-Film Solar Cells T2 - 28th Workshop on Quantum Solar Energy Conversion - (QUANTSOL) Y1 - 2016 ER - TY - JOUR A1 - Barth, Carlo A1 - Probst, Jürgen A1 - Herrmann, Sven A1 - Hammerschmidt, Martin A1 - Becker, Christiane T1 - Numerical characterization of symmetry properties for photonic crystals with hexagonal lattice JF - Proc. SPIE N2 - We present a numerical method to characterize the symmetry properties of photonic crystal (PhC) modes based on field distributions, which themselves can be obtained numerically. These properties can be used to forecast specific features of the optical response of such systems, e.g. which modes are allowed to couple to external radiation fields. We use 2D PhCs with a hexagonal lattice of holes in dielectric as an example and apply our technique to reproduce results from analytical considerations. Further, the method is extended to fully vectorial problems in view of 3D PhCs and PhC slabs, its functionality is demonstrated using test cases and, finally, we provide an efficient implementation. The technique can thus readily be applied to output data of all band structure computation methods or even be embedded – gaining additional information about the mode symmetry. Y1 - 2016 U6 - https://doi.org/10.1117/12.2227094 VL - 9885 SP - 988506 ER -