@article{KirnerHammerschmidtSchwankeetal.2014, author = {Kirner, Simon and Hammerschmidt, Martin and Schwanke, Christoph and Lockau, Daniel and Calnan, Sonya and Frijnts, Tim and Neubert, Sebastian and Sch{\"o}pke, Andreas and Schmidt, Frank and Zollondz, Jens-Hendrik and Heidelberg, Andreas and Stannowski, Bernd and Rech, Bernd and Schlatmann, Rutger}, title = {Implications of TCO Topography on Intermediate Reflector Design for a-Si/μc-Si Tandem Solar Cells — Experiments and Rigorous Optical Simulations}, series = {IEEE Journal of Photovoltaics}, volume = {4}, journal = {IEEE Journal of Photovoltaics}, number = {1}, doi = {10.1109/JPHOTOV.2013.2279204}, pages = {10 -- 15}, year = {2014}, language = {en} } @inproceedings{BarthRoderBrodoceanuetal., author = {Barth, Carlo and Roder, Sebastian and Brodoceanu, Daniel and Kraus, Tobias and Burger, Sven and Hammerschmidt, Martin and Schmidt, Frank and Becker, Christiane}, title = {Increased fluorescence of PbS quantum dots on photonic crystal slab structures}, series = {Proc. Europ. Opt. Soc. Ann. Meet. 2016 (EOSAM)}, booktitle = {Proc. Europ. Opt. Soc. Ann. Meet. 2016 (EOSAM)}, isbn = {978-1-5108-4796-5}, pages = {181}, 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} } @misc{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}, issn = {1438-0064}, doi = {10.1117/12.2212367}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-57239}, 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 modeling and numerical accuracy atcomputational 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-scatteringoptical wavelengths off 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} } @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} } @misc{HammerschmidtLockauZschiedrichetal., author = {Hammerschmidt, Martin and Lockau, Daniel and Zschiedrich, Lin and Schmidt, Frank}, title = {Optical modelling of incoherent substrate light-trapping in silicon thin film multi-junction solar cells with finite elements and domain decomposition}, issn = {1438-0064}, doi = {10.1117/12.2036346}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-50410}, abstract = {In many experimentally realized applications, e.g. photonic crystals, solar cells and light-emitting diodes, nano-photonic systems are coupled to a thick substrate layer, which in certain cases has to be included as a part of the optical system. The finite element method (FEM) yields rigorous, high accuracy solutions of full 3D vectorial Maxwell's equations [1] and allows for great flexibility and accuracy in the geometrical modelling. Time-harmonic FEM solvers have been combined with Fourier methods in domain decomposition algorithms to compute coherent solutions of these coupled system. [2,3] The basic idea of a domain decomposition approach lies in a decomposition of the domain into smaller subdomains, separate calculations of the solutions and coupling of these solutions on adjacent subdomains. In experiments light sources are often not perfectly monochromatic and hence a comparision to simulation results might only be justified if the simulation results, which include interference patterns in the substrate, are spectrally averaged. In this contribution we present a scattering matrix domain decomposition algorithm for Maxwell's equations based on FEM. We study its convergence and advantages in the context of optical simulations of silicon thin film multi-junction solar cells. This allows for substrate light-trapping to be included in optical simulations and leads to a more realistic estimation of light path enhancement factors in thin-film devices near the band edge.}, language = {en} } @inproceedings{HammerschmidtLockauZschiedrichetal.2014, author = {Hammerschmidt, Martin and Lockau, Daniel and Zschiedrich, Lin and Schmidt, Frank}, title = {Optical modelling of incoherent substrate light-trapping in silicon thin film multi-junction solar cells with finite elements and domain decomposition}, series = {Proc. SPIE: Physics and Simulation of Optoelectronic Devices XXII}, volume = {8980}, booktitle = {Proc. SPIE: Physics and Simulation of Optoelectronic Devices XXII}, publisher = {SPIE}, doi = {10.1117/12.2036346}, pages = {898007}, year = {2014}, language = {en} } @misc{LockauHammerschmidtBlomeetal., author = {Lockau, Daniel and Hammerschmidt, Martin and Blome, Mark and Schmidt, Frank}, title = {Optics of thin film solar cells}, series = {MATHEON-Mathematics for Key Technologies}, volume = {1}, journal = {MATHEON-Mathematics for Key Technologies}, editor = {Deuflhard, Peter and et al.,}, publisher = {European Mathematical Society}, doi = {10.4171/137}, pages = {278 -- 279}, 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} } @misc{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}, issn = {1438-0064}, doi = {10.1117/12.2212482}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-57249}, 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} }