@inbook{3836, abstract = {{We apply the Discontinuous Galerkin Time Domain (DGTD) method for numerical simulations of the second harmonic generation from various metallic nanostructures. A Maxwell–Vlasov hydrodynamic model is used to describe the nonlinear effects in the motion of the excited free electrons in a metal. The results are compared with the corresponding experimental measurements for split-ring resonators and plasmonic gap antennas.}}, author = {{Grynko, Yevgen and Förstner, Jens}}, booktitle = {{Recent Trends in Computational Photonics}}, editor = {{Agrawal, Arti}}, isbn = {{9783319554372}}, issn = {{0342-4111}}, keywords = {{tet_topic_numerics, tet_topic_shg, tet_topic_meta}}, pages = {{261--284}}, publisher = {{Springer International Publishing}}, title = {{{Simulation of Second Harmonic Generation from Photonic Nanostructures Using the Discontinuous Galerkin Time Domain Method}}}, doi = {{10.1007/978-3-319-55438-9_9}}, year = {{2017}}, } @article{680, author = {{Peter, Manuel and Hildebrandt, Andre and Schlickriede, Christian and Gharib, Kimia and Zentgraf, Thomas and Förstner, Jens and Linden, Stefan}}, issn = {{1530-6984}}, journal = {{Nano Letters}}, keywords = {{tet_topic_opticalantenna}}, number = {{7}}, pages = {{4178--4183}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Directional Emission from Dielectric Leaky-Wave Nanoantennas}}}, doi = {{10.1021/acs.nanolett.7b00966}}, volume = {{17}}, year = {{2017}}, } @inproceedings{1592, abstract = {{Compared to classical HDL designs, generating FPGA with high-level synthesis from an OpenCL specification promises easier exploration of different design alternatives and, through ready-to-use infrastructure and common abstractions for host and memory interfaces, easier portability between different FPGA families. In this work, we evaluate the extent of this promise. To this end, we present a parameterized FDTD implementation for photonic microcavity simulations. Our design can trade-off different forms of parallelism and works for two independent OpenCL-based FPGA design flows. Hence, we can target FPGAs from different vendors and different FPGA families. We describe how we used pre-processor macros to achieve this flexibility and to work around different shortcomings of the current tools. Choosing the right design configurations, we are able to present two extremely competitive solutions for very different FPGA targets, reaching up to 172 GFLOPS sustained performance. With the portability and flexibility demonstrated, code developers not only avoid vendor lock-in, but can even make best use of real trade-offs between different architectures.}}, author = {{Kenter, Tobias and Förstner, Jens and Plessl, Christian}}, booktitle = {{Proc. Int. Conf. on Field Programmable Logic and Applications (FPL)}}, keywords = {{tet_topic_hpc}}, publisher = {{IEEE}}, title = {{{Flexible FPGA design for FDTD using OpenCL}}}, doi = {{10.23919/FPL.2017.8056844}}, year = {{2017}}, } @article{35, author = {{Linnenbank, Heiko and Grynko, Yevgen and Förstner, Jens and Linden, Stefan}}, issn = {{2047-7538}}, journal = {{Light: Science & Applications}}, keywords = {{tet_topic_opticalantenna, tet_topic_shg}}, number = {{1}}, pages = {{e16013}}, publisher = {{Springer Nature}}, title = {{{Second harmonic generation spectroscopy on hybrid plasmonic/dielectric nanoantennas}}}, doi = {{10.1038/lsa.2016.13}}, volume = {{5}}, year = {{2016}}, } @inproceedings{3543, author = {{Hildebrandt, Andre and Alhaddad, Samer and Hammer, Manfred and Förstner, Jens}}, booktitle = {{Integrated Optics: Devices, Materials, and Technologies XX}}, editor = {{Broquin, Jean-Emmanuel and Nunzi Conti, Gualtiero}}, keywords = {{tet_topic_waveguide}}, publisher = {{SPIE}}, title = {{{Oblique incidence of semi-guided waves on step-like folds in planar dielectric slabs: Lossless vertical interconnects in 3D integrated photonic circuits}}}, doi = {{10.1117/12.2214460}}, year = {{2016}}, } @article{3834, abstract = {{The problem of light scattering by ice crystals of cirrus clouds is considered in the case of a hexagonal ice plate with different distributions over crystal orientations. The physical-optics approximation based on (E, M)-diffraction theory is compared with two exact numerical methods: the finite difference time domain (FDTD) and the discontinuous Galerkin time domain (DGTD) in order to estimate its accuracy and limits of applicability. It is shown that the accuracy of the physical-optics approximation is estimated as 95% for the averaged backscattering Mueller matrix for particles with size parameter more than 120. Furthermore, the simple expression that allows one to estimate the minimal number of particle orientations required for appropriate spatial averaging has been derived.}}, author = {{Konoshonkin, Alexander and Borovoi, Anatoli and Kustova, Natalia and Okamoto, Hajime and Ishimoto, Hiroshi and Grynko, Yevgen and Förstner, Jens}}, issn = {{0022-4073}}, journal = {{Journal of Quantitative Spectroscopy and Radiative Transfer}}, keywords = {{tet_topic_scattering}}, pages = {{132--140}}, publisher = {{Elsevier BV}}, title = {{{Light scattering by ice crystals of cirrus clouds: From exact numerical methods to physical-optics approximation}}}, doi = {{10.1016/j.jqsrt.2016.12.024}}, volume = {{195}}, year = {{2016}}, } @inproceedings{3840, abstract = {{In the problem of light scattering by ice crystals of cirrus clouds, two exact methods (FDTD – finite difference time domain and DGTD – discontinuous Galerkin time domain) and the physical-optics approximation are used for numerical calculations of the Mueller matrix in the case of ice hexagonal plates and columns. It is shown that for the crystals larger than 10 μm at the wavelength of 0.532 μm the exact methods and physical-optics approximation closely agreed within three diffraction fringes about the centers of the diffraction patterns. As a result, in the case of random orientation of these crystals, the physical-optics approximation provides accuracy 95% for the averaged Mueller matrix.}}, author = {{Konoshonkin, Alexander V. and Kustova, Natalia V. and Borovoi, Anatoli G. and Okamoto, H. and Sato, K. and Ishimoto, H. and Grynko, Yevgen and Förstner, Jens}}, booktitle = {{22nd International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics}}, editor = {{Matvienko, Gennadii G. and Romanovskii, Oleg A.}}, keywords = {{tet_topic_scattering}}, publisher = {{SPIE}}, title = {{{Comparison between the physical-optics approximation and exact methods solving the problem of light scattering by ice crystals of cirrus clouds}}}, doi = {{10.1117/12.2248409}}, year = {{2016}}, } @article{3841, abstract = {{We present phase sensitive cavity field measurements on photonic crystal microcavities. The experiments have been performed as autocorrelation measurements with ps double pulse laser excitation for resonant and detuned conditions. Measured E-field autocorrelation functions reveal a very strong detuning dependence of the phase shift between laser and cavity field and of the autocorrelation amplitude of the cavity field. The fully resolved phase information allows for a precise frequency discrimination and hence for a precise measurement of the detuning between laser and cavity. The behavior of the autocorrelation amplitude and phase and their detuning dependence can be fully described by an analytic model. Furthermore, coherent control of the cavity field is demonstrated by tailored laser excitation with phase and amplitude controlled pulses. The experimental proof and verification of the above described phenomena became possible by an electric detection scheme, which employs planar photonic crystal microcavity photo diodes with metallic Schottky contacts in the defect region of the resonator. The applied photo current detection was shown to work also efficiently at room temperature, which make electrically contacted microcavities attractive for real world applications.}}, author = {{Quiring, Wadim and Jonas, Björn and Förstner, Jens and Rai, Ashish K. and Reuter, Dirk and Wieck, Andreas D. and Zrenner, Artur}}, issn = {{1094-4087}}, journal = {{Optics Express}}, keywords = {{tet_topic_phc}}, number = {{18}}, pages = {{20672--20684}}, publisher = {{The Optical Society}}, title = {{{Phase sensitive properties and coherent manipulation of a photonic crystal microcavity}}}, doi = {{10.1364/oe.24.020672}}, volume = {{24}}, year = {{2016}}, } @article{3843, abstract = {{We simulate light scattering by random irregular particles that have dimensions much larger than the wavelength of incident light at the size parameter of 𝑋=200 using the discontinuous Galerkin time domain method. A comparison of the DGTD solution for smoothly faceted particles with that obtained with a geometric optics model shows good agreement for the scattering angle curves of intensity and polarization. If a wavelength-scale surface roughness is introduced, diffuse scattering at rough interface results in smooth and featureless curves for all scattering matrix elements which is consistent with the laboratory measurements of real samples.}}, author = {{Grynko, Yevgen and Shkuratov, Yuriy and Förstner, Jens}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, keywords = {{tet_topic_scattering}}, number = {{15}}, pages = {{3491--3493}}, publisher = {{The Optical Society}}, title = {{{Light scattering by irregular particles much larger than the wavelength with wavelength-scale surface roughness}}}, doi = {{10.1364/ol.41.003491}}, volume = {{41}}, year = {{2016}}, } @article{3849, abstract = {{The physical optics approximations are derived from the Maxwell equations. The scattered field equations by Kirchhoff, Stratton-Chu, Kottler and Franz are compared and discussed. It is shown that in the case of faceted particles, these equations reduce to a sum of the diffraction integrals, where every diffraction integral is associated with one plane–parallel optical beam leaving a particle facet. In the far zone, these diffraction integrals correspond to the Fraunhofer diffraction patterns. The paper discusses the E-, M- and (E, M)-diffraction theories as applied to ice crystals of cirrus clouds. The comparison to the exact solution obtained by the discontinuous Galerkin time domain method shows that the Kirchhoff diffraction theory is preferable.}}, author = {{Konoshonkin, Alexander V. and Kustova, Natalia V. and Borovoi, Anatoli G. and Grynko, Yevgen and Förstner, Jens}}, issn = {{0022-4073}}, journal = {{Journal of Quantitative Spectroscopy and Radiative Transfer}}, keywords = {{tet_topic_scattering}}, pages = {{12--23}}, publisher = {{Elsevier BV}}, title = {{{Light scattering by ice crystals of cirrus clouds: comparison of the physical optics methods}}}, doi = {{10.1016/j.jqsrt.2016.05.006}}, volume = {{182}}, year = {{2016}}, } @article{3884, abstract = {{e study the discrete soliton formation in one- and two- dimensional arrays of nanowires coated with graphene monolayers. Highly confined solitons, including the fundamental and the higher-order modes, are found to be supported by the proposed structure with a low level of power flow. Numerical analysis reveals that, by tuning the input intensity and Fermi energy, the beam diffraction, soliton dimension and propagation loss can be fully controlled in a broad range, indicating potential values of the graphene-based solitons in nonlinear/active nanophotonic systems. }}, author = {{Kou, Yao and Förstner, Jens}}, issn = {{1094-4087}}, journal = {{Optics Express}}, keywords = {{tet_topic_plasmonics, tet_topic_polariton}}, number = {{5}}, pages = {{4714}}, publisher = {{The Optical Society}}, title = {{{Discrete plasmonic solitons in graphene-coated nanowire arrays}}}, doi = {{10.1364/oe.24.004714}}, volume = {{24}}, year = {{2016}}, } @article{3886, abstract = {{ We report on second harmonic generation spectroscopy on a series of rectangular arrays of split-ring resonators. Within the sample series, the lattice constants are varied, but the area of the unit cell is kept fixed. The SHG signal intensity of the different arrays upon resonant excitation of the fundamental plasmonic mode strongly depends on the respective arrangement of the split-ring resonators. This finding can be explained by variations of the electromagnetic interactions between the split-ring resonators in the different arrays. The experimental results are in agreement with numerical calculations based on the discontinuous Galerkin time-domain method. (PDF) The role of electromagnetic interactions.... Available from: https://www.researchgate.net/publication/297612326_The_role_of_electromagnetic_interactions_in_second_harmonic_generation_from_plasmonic_metamaterials [accessed Aug 13 2018].}}, author = {{Alberti, Julian and Linnenbank, Heiko and Linden, Stefan and Grynko, Yevgen and Förstner, Jens}}, issn = {{0946-2171}}, journal = {{Applied Physics B}}, keywords = {{tet_topic_shg, tet_topic_meta}}, number = {{2}}, pages = {{45--50}}, publisher = {{Springer Nature}}, title = {{{The role of electromagnetic interactions in second harmonic generation from plasmonic metamaterials}}}, doi = {{10.1007/s00340-015-6311-x}}, volume = {{122}}, year = {{2016}}, } @inproceedings{3934, abstract = {{Typical optical integrated circuits combine elements, like straight and curved waveguides, or cavities, the simulation and design of which is well established through numerical eigenproblem-solvers. It remains to predict the interaction of these modes. We address this task by a ”Hybrid” variant (HCMT) of Coupled Mode Theory. Using methods from finite-element numerics, the optical properties of a circuit are approximated by superpositions of eigen-solutions for its constituents, leading to quantitative, low-dimensional, and interpretable models in the frequency domain. Spectral scans are complemented by the direct computation of supermode properties (spectral positions and linewidths, coupling-induced phase shifts). This contribution outlines the theoretical background, and discusses briefly limitations and implementational details, with the help of an example of a 2-D coupled-resonator-optical-waveguide configuration.}}, author = {{Hammer, Manfred}}, booktitle = {{Integrated Optics: Devices, Materials, and Technologies XX}}, editor = {{Broquin, Jean-Emmanuel and Nunzi Conti, Gualtiero}}, keywords = {{tet_topic_waveguide, tet_topic_numerics}}, location = {{San Francisco, USA}}, number = {{9750}}, pages = {{975018--975018--8 }}, publisher = {{SPIE}}, title = {{{Wave interaction in photonic integrated circuits: Hybrid analytical / numerical coupled mode modeling}}}, doi = {{10.1117/12.2214331}}, year = {{2016}}, } @article{3888, abstract = {{We successfully developed a process to fabricate freestanding cubic aluminium nitride (c-AlN) membranes containing cubic gallium nitride (c-GaN) quantum dots (QDs). The samples were grown by plasma assisted molecular beam epitaxy (MBE). To realize the photonic crystal (PhC) membrane we have chosen a triangular array of holes. The array was fabricated by electron beam lithography and several steps of reactive ion etching (RIE) with the help of a hard mask and an undercut of the active layer. The r/a- ratio of 0.35 was deter- mined by numerical simulations to obtain a preferably wide photonic band gap. Micro-photoluminescence (μ-PL) measurements of the photonic crystals, in particular of a H1 and a L3 cavity, and the emission of the QD ensemble were performed to characterize the samples. The PhCs show high quality factors of 4400 for the H1 cavity and about 5000/3000 for two different modes of the L3 cavity, respectively. The energy of the fundamental modes is in good agreement to the numerical simulations. }}, author = {{Blumenthal, Sarah and Bürger, Matthias and Hildebrandt, Andre and Förstner, Jens and Weber, Nils and Meier, Cedrik and Reuter, Dirk and As, Donat J.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_phc, tet_topic_qd}}, number = {{5-6}}, pages = {{292--296}}, publisher = {{Wiley}}, title = {{{Fabrication and characterization of two-dimensional cubic AlN photonic crystal membranes containing zincblende GaN quantum dots}}}, doi = {{10.1002/pssc.201600010}}, volume = {{13}}, year = {{2016}}, } @article{1454, author = {{Grynko, Yevgen and Zentgraf, Thomas and Meier, Torsten and Förstner, Jens}}, issn = {{0946-2171}}, journal = {{Applied Physics B}}, keywords = {{tet_topic_meta, tet_topic_shg}}, number = {{9}}, pages = {{242}}, publisher = {{Springer Nature}}, title = {{{Simulations of high harmonic generation from plasmonic nanoparticles in the terahertz region}}}, doi = {{10.1007/s00340-016-6510-0}}, volume = {{122}}, year = {{2016}}, } @article{3845, abstract = {{The device principle of a prism-based on-chip spectrometer for TE polarization is introduced. The spectrometer exploits the modal dispersion in planar waveguides in a layout with slab regions having two different thicknesses of the guiding layer. The set-up uses parabolic mirrors, for the collimation of light of the input waveguide and focusing of the light to the receiver waveguides, which relies on total internal reflection at the interface between two such regions. These regions are connected adiabatically to prevent unwanted mode conversion and loss at the edges of the prism. The structure can be fabricated with two wet etching steps. The paper presents basic theory and a general approach for device optimization. The latter is illustrated with a numerical example assuming SiON technology.}}, author = {{Civitci, F. and Hammer, Manfred and Hoekstra, H.J.W.M.}}, issn = {{0030-4018}}, journal = {{Optics Communications}}, keywords = {{tet_topic_waveguide}}, pages = {{29--37}}, publisher = {{Elsevier BV}}, title = {{{Planar prism spectrometer based on adiabatically connected waveguiding slabs}}}, doi = {{10.1016/j.optcom.2015.11.066}}, volume = {{365}}, year = {{2015}}, } @article{3847, abstract = {{Sheets of slab waveguides with sharp corners are investigated. By means of rigorous numerical experiments, we look at oblique incidence of semi-guided plane waves. Radiation losses vanish beyond a certain critical angle of incidence. One can thus realize lossless propagation through 90-degree corner configurations, where the remaining guided waves are still subject to pronounced reflection and polarization conversion. A system of two corners can be viewed as a structure akin to a Fabry-Perot-interferometer. By adjusting the distance between the two partial reflectors, here the 90-degree corners, one identifies step-like configurations that transmit the semi-guided plane waves without radiation losses, and virtually without reflections. Simulations of semi-guided beams with in-plane wide Gaussian profiles show that the effect survives in a true 3-D framework.}}, author = {{Hammer, Manfred and Hildebrandt, Andre and Förstner, Jens}}, issn = {{0733-8724}}, journal = {{Journal of Lightwave Technology}}, keywords = {{tet_topic_waveguide}}, number = {{3}}, pages = {{997--1005}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Full Resonant Transmission of Semiguided Planar Waves Through Slab Waveguide Steps at Oblique Incidence}}}, doi = {{10.1109/jlt.2015.2502431}}, volume = {{34}}, year = {{2015}}, } @article{3892, abstract = {{Plasmon modes of the exact same individual gold nanoprisms are investigated through combined nanometer-resolved electron energy-loss spectroscopy (EELS) and cathodoluminescence (CL) measurements. We show that CL only probes the radiative modes, in contrast to EELS, which additionally reveals dark modes. The combination of both techniques on the same particles thus provides complementary information and also demonstrates that although the radiative modes give rise to very similar spatial distributions when probed by EELS or CL, their resonant energies appear to be different. We trace this phenomenon back to plasmon dissipation, which affects in different ways the plasmon signatures probed by these techniques. Our experiments are in agreement with electromagnetic numerical simulations and can be further interpreted within the framework of a quasistatic analytical model. We therefore demonstrate that CL and EELS are closely related to optical scattering and extinction, respectively, with the addition of nanometer spatial resolution.}}, author = {{Losquin, Arthur and Zagonel, Luiz F. and Myroshnychenko, Viktor and Rodríguez-González, Benito and Tencé, Marcel and Scarabelli, Leonardo and Förstner, Jens and Liz-Marzán, Luis M. and García de Abajo, F. Javier and Stéphan, Odile and Kociak, Mathieu}}, issn = {{1530-6984}}, journal = {{Nano Letters}}, keywords = {{tet_topic_plasmonics}}, number = {{2}}, pages = {{1229--1237}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Unveiling Nanometer Scale Extinction and Scattering Phenomena through Combined Electron Energy Loss Spectroscopy and Cathodoluminescence Measurements}}}, doi = {{10.1021/nl5043775}}, volume = {{15}}, year = {{2015}}, } @article{3894, abstract = {{We show how to optically connect guiding layers at different elevations in a 3-D integrated photonic circuit. Transfer of optical power carried by planar, semi-guided waves is possible without reflections or radiation losses, and over large vertical distances. This functionality is realized through simple step-like folds of high-contrast dielectric slab waveguides, in combination with oblique wave incidence, and fulfilling a resonance condition. Radiation losses vanish, and polarization conversion is suppressed for TE wave incidence beyond certain critical angles. This can be understood by fundamental arguments resting on a version of Snell’s law. The two 90° corners of a step act as identical partial reflectors in a Fabry–Perot-like resonator setup. By selecting the step height, i.e., the distance between the reflectors, one realizes resonant states with full transmission. Rigorous quasi-analytical simulations for typical silicon/silica parameters demonstrate the functioning. Combinations of several step junctions can lead to other types of optical on-chip connects, e.g., U-turn- or bridge-like configurations.}}, author = {{Hammer, Manfred and Hildebrandt, Andre and Förstner, Jens}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, keywords = {{tet_topic_waveguide}}, number = {{16}}, pages = {{3711--3714}}, publisher = {{The Optical Society}}, title = {{{How planar optical waves can be made to climb dielectric steps}}}, doi = {{10.1364/ol.40.003711}}, volume = {{40}}, year = {{2015}}, } @article{3896, abstract = {{We study the formation of subwavelength solitons in binary metal-dielectric lattices. We show that the transverse modulation of the lattice constant breaks the fundamental plasmonic band and suppresses the discrete diffraction of surface plasmon waves. New types of plasmonic solitons are found, and their characteristics are analyzed. We also demonstrate the existence of photonic-plasmonic vector solitons and elucidate their propagation properties.}}, author = {{Kou, Yao and Förstner, Jens}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, keywords = {{tet_topic_polariton}}, number = {{6}}, pages = {{851--854}}, publisher = {{The Optical Society}}, title = {{{Subwavelength binary plasmonic solitons}}}, doi = {{10.1364/ol.40.000851}}, volume = {{40}}, year = {{2015}}, }