@inproceedings{HammerschmidtLockauBurgeretal.2012, author = {Hammerschmidt, Martin and Lockau, Daniel and Burger, Sven and Schmidt, Frank and Schwanke, Christoph and Kirner, Simon and Calnan, Sonya and Stannowski, Bernd and Rech, Bernd}, title = {3D optical modeling of thin-film a-Si/mc-Si tandem solar cells with random textured interfaces using FEM}, series = {Renewable Energy and the Environment Optics and Photonics Congress}, booktitle = {Renewable Energy and the Environment Optics and Photonics Congress}, publisher = {Optical Society of America}, doi = {10.1364/E2.2012.JM5A.15}, pages = {JM5A.15}, year = {2012}, language = {en} } @article{HammerschmidtLockauBurgeretal.2013, author = {Hammerschmidt, Martin and Lockau, Daniel and Burger, Sven and Schmidt, Frank and Schwanke, Christoph and Kirner, Simon and Calnan, Sonya and Stannowski, Bernd and Rech, Bernd}, title = {FEM-based optical modeling of silicon thin-film tandem solar cells with randomly textured interfaces in 3D}, series = {Proc. SPIE}, volume = {8620}, journal = {Proc. SPIE}, doi = {10.1117/12.2001789}, pages = {86201H}, year = {2013}, language = {en} } @inproceedings{ZschiedrichGreinerPomplunetal.2012, author = {Zschiedrich, Lin and Greiner, Horst and Pomplun, Jan and Hammerschmidt, Martin and Burger, Sven and Schmidt, Frank}, title = {FEM simulations of light extraction from nanostructured organic light-emitting diodes}, series = {Renewable Energy and the Environment Optics and Photonics Congress}, booktitle = {Renewable Energy and the Environment Optics and Photonics Congress}, publisher = {Optical Society of America}, doi = {10.1364/SOLED.2012.LT2B.5}, pages = {LT2B.5}, year = {2012}, language = {en} } @article{GutschePoulikakosHammerschmidtetal., author = {Gutsche, Philipp and Poulikakos, Lisa and Hammerschmidt, Martin and Burger, Sven and Schmidt, Frank}, title = {Time-harmonic optical chirality in inhomogeneous space}, series = {Proc. SPIE}, volume = {9756}, journal = {Proc. SPIE}, doi = {10.1117/12.2209551}, pages = {97560X}, language = {en} } @misc{GutschePoulikakosBurgeretal., author = {Gutsche, Philipp and Poulikakos, Lisa and Burger, Sven and Hammerschmidt, Martin and Schmidt, Frank}, title = {Optical chirality: conservation law in arbitrary space}, series = {606. WE-Heraeus-Seminar on Nanophotonics and Complex Spatial Modes of Light}, journal = {606. WE-Heraeus-Seminar on Nanophotonics and Complex Spatial Modes of Light}, abstract = {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.}, language = {en} } @article{HammerschmidtBarthPomplunetal., author = {Hammerschmidt, Martin and Barth, Carlo and Pomplun, Jan and Burger, Sven and Becker, Christiane and Schmidt, Frank}, title = {Reconstruction of photonic crystal geometries using a reduced basis method for nonlinear outputs}, series = {Proc. SPIE}, volume = {9756}, journal = {Proc. SPIE}, doi = {10.1117/12.2212482}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-58187}, pages = {97561R}, abstract = {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.}, language = {en} } @article{HammerschmidtHerrmannPomplunetal., author = {Hammerschmidt, Martin and Herrmann, Sven and Pomplun, Jan and Burger, Sven and Schmidt, Frank}, title = {Model order reduction for the time-harmonic Maxwell equation applied to complex nanostructures}, series = {Proc. SPIE}, volume = {9742}, journal = {Proc. SPIE}, doi = {10.1117/12.2212367}, pages = {97420M}, abstract = {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.}, language = {en} } @article{HammerschmidtHerrmannPomplunetal., author = {Hammerschmidt, Martin and Herrmann, Sven and Pomplun, Jan and Burger, Sven and Schmidt, Frank}, title = {Reduced basis method for electromagnetic scattering problem: a case study for FinFETs}, series = {Optical and Quantum Electronics}, volume = {48}, journal = {Optical and Quantum Electronics}, doi = {10.1007/s11082-016-0530-1}, pages = {250}, abstract = {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.}, language = {en} } @article{JaegerBarthHammerschmidtetal., author = {J{\"a}ger, Klaus and Barth, Carlo and Hammerschmidt, Martin and Herrmann, Sven and Burger, Sven and Schmidt, Frank and Becker, Christiane}, title = {Simulations of sinusoidal nanotextures for coupling light into c-Si thin-film solar cells}, series = {Opt. Express}, volume = {24}, journal = {Opt. Express}, doi = {10.1364/OE.24.00A569}, pages = {A569}, language = {en} } @misc{HammerschmidtPomplunBurgeretal., author = {Hammerschmidt, Martin and Pomplun, Jan and Burger, Sven and Schmidt, Frank}, title = {Adaptive sampling strategies for efficient parameter scans in nano-photonic device simulations}, issn = {1438-0064}, doi = {10.1117/12.2036363}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-50395}, abstract = {Rigorous optical simulations are an important tool in optimizing scattering properties of nano-photonic devices and are used, for example, in solar cell optimization. The finite element method (FEM) yields rigorous, time-harmonic, high accuracy solutions of the full 3D vectorial Maxwell's equations [1] and furthermore allows for great flexibility and accuracy in the geometrical modeling of these often complex shaped 3D nano-structures. A major drawback of frequency domain methods is the limitation of single frequency evaluations. For example the accurate computation of the short circuit current density of an amorphous silicon / micro-crystalline multi-junction thin film solar cell may require the solution of Maxwell's equations for over a hundred different wavelengths if an equidistant sampling strategy is employed. Also in optical metrology, wavelength scans are frequently used to reconstruct unknown geometrical and material properties of optical systems numerically from measured scatterometric data. In our contribution we present several adaptive numerical integration and sampling routines and study their efficiency in the context of the determination of generation rate profiles of solar cells. We show that these strategies lead to a reduction in the computational effort without loss of accuracy. We discuss the employment of tangential information in a Hermite interpolation scheme to achieve similar accuracy on coarser grids. We explore the usability of these strategies for scatterometry and solar cell simulations.}, language = {en} }