TY - JOUR A1 - Lux, Helge A1 - Edling, Matthias A1 - Lucci, Massimiliano A1 - Kitzmann, Julia A1 - Villringer, Claus A1 - Siemroth, Peter A1 - De Matteis, Fabio A1 - Schrader, Sigurd T1 - The Role of Substrate Temperature and Magnetic Filtering for DLC by Cathodic Arc Evaporation JF - Coatings N2 - Diamond-like carbon (DLC) films were deposited using two different types of high current arc evaporation. The first process used a magnetic particle filter to remove droplets from the plasma. For the second process, the samples were put into a metallic cage which was placed directly above the plasma source. For both processes, we varied the substrate temperature from 21 to 350 °C in order to investigate the temperature effect. The samples were characterized using SEM, AFM, XPS, Raman Spectroscopy, Ellipsometry, Photometry, and Nano Indentation in order to compare both methods of deposition and provide a careful characterization of such DLC films. We found that the sp3 content and the hardness can be precisely adjusted by changing the substrate temperature. Furthermore, in the case of unfiltered deposition, the optical constants can be shifted in the direction of higher absorbance in order to produce black and hard carbon coatings. KW - DLC KW - ta-C KW - arc evaporation KW - substrate temperature KW - hardness KW - optical constant KW - ellipsometry Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12295 SN - 2079-6412 VL - 9 IS - 5 SP - 345 ER - TY - JOUR A1 - Steglich, Patrick A1 - Villringer, Claus A1 - Dietzel, Birgit A1 - Mai, Christian A1 - Schrader, Sigurd A1 - Casalboni, Mauro A1 - Mai, Andreas T1 - On-Chip Dispersion Measurement of the Quadratic Electro-Optic Effect in Nonlinear Optical Polymers Using a Photonic Integrated Circuit Technology JF - IEEE Photonics Journal N2 - A novel method to determine the dispersion of the quadratic electro-optic effect in nonlinear optical materials by using a silicon-on-insulator microring resonator is presented. The microring consists of a silicon slot waveguide enabling large dc electric field strength at low applied voltages. The dispersion of third-order hyperpolarizability of a linear conjugated dye is approximated by using a two-level model for the off-resonant spectral region. As an example, the dispersion of the resonance wavelength of the resonator filled with a dye doped polymer was measured in dependence of the applied dc voltage. The polymer was poly (methylmethacrylate) doped with 5 wt% disperse red 1 (DR1), and the measurements have been carried out at the telecommunication wavelength band around 1550 nm (optical C-band). The described measurements represent a new technique to determine the dispersion of the third-order susceptibility and molecular hyperpolarizability of the material filled into the slot of the ring-resonator. KW - electro-optical device KW - nonlinear optics KW - integrated optics KW - integrated optics material KW - optical material KW - integrated optics device KW - polymer active device Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-12307 SN - 1943-0655 VL - 11 IS - 3 ER - TY - JOUR A1 - Lux, Helge A1 - Edling, Matthias A1 - Siemroth, Peter A1 - Schrader, Sigurd T1 - Fast and Cost-Effective Synthesis of High-Quality Graphene on Copper Foils Using High-Current Arc Evaporation JF - Materials N2 - In this paper, we present an innovative and ultra-fast process for the deposition of high-quality graphene on different metal foils and thin metal films. The graphene layer can be homogeneously deposited in only 30 s process time. Due to the weak adhesion to the substrate material, the monolayer graphene is easy to transfer using the established processes. For the production, we use magnetic filtered high-current arc evaporation (Φ-HCA) with a solid, graphitic carbon source. This ultra-fast growth process can pave the way towards a cost-effective graphene synthesis for the mass production e.g., in a roll-to-roll process, avoiding time consuming established processes. KW - graphene KW - PVD KW - arc evaporation KW - copper KW - transfer KW - Φ-HCA Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-10359 SN - 1996-1944 VL - 11 IS - 5 SP - 1 EP - 10 ER - TY - JOUR A1 - Grytsenko, Kostyantyn A1 - Ksianzou, Viachaslau A1 - Kolomzarov, Yurii A1 - Lytvyn, Peter A1 - Dietzel, Birgit A1 - Schrader, Sigurd T1 - Fluoropolymer Film Formation by Electron Activated Vacuum Deposition JF - Surfaces N2 - Polytetrafluoroethylene (PTFE), polyhexafluoropropylene (PHFP) and polychlorotrifluoroethylene (PCTFE) were heated to their decomposition temperature in a high vacuum. The emitted fragments passed an electron cloud, condensed on a substrate and formed fluoropolymer film. Growth rate of PTFE and PHFP films increased up to a factor five in the presence of the electron cloud. Mass spectrometry revealed changes in the mass spectra of fragments generated by thermal decomposition only and formed under electron activation. The observed changes were different for each fluoropolymer. Infrared spectroscopy (IRS) showed that the structure of the films was close to the structure of the bulk polymers. Atomic force microscopy (AFM) has revealed different morphologies of PTFE, PHFP and PCTFE films, suggesting a Volmer–Weber growth mechanism for PTFE and PHFP but a Frank-van der Merwe one for PCTFE. All films were smooth at nanoscale and transparent from ultraviolet to near-infrared region. Additional radio frequency (RF) plasma ignited in the emitted fragments at a low pressure increased mechanical characteristics of the films without losing their optical transparency and smoothness. KW - fluoropolymer thin film KW - vacuum deposition KW - polymerization KW - plasma KW - surface Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13786 SN - 2571-9637 VL - 4 IS - 1 SP - 66 EP - 80 PB - MDPI ER - TY - GEN A1 - Beyer, Harald A1 - Hofmann, Mandy A1 - Trutz, Sebastian A1 - Lux, Helge A1 - Stissel, Sven A1 - Mehr, Wolfgang A1 - Schrader, Sigurd A1 - Siemroth, Peter T1 - Großflächige Abscheidung von Graphen - Ein wichtiger Schritt für neuartige Bauelemente T2 - Wissenschaftliche Beiträge 2013 N2 - Das wachsende Interesse an Graphen beruht auf seiner unverwechselbaren Bandstruktur und seinen damit zusammenhängenden herausragenden physikalischen Eigenschaften. Es wird daher weltweit nach einem Verfahren gesucht, Graphen großflächig und mit hoher Qualität abzuscheiden. In einer an der TH Wildau [FH] speziell für diese Aufgabe konzipierten Reaktionskammer wurde die Herstellung mittels chemischer Gasphasenabscheidung auf katalytischen Metalloberflächen für verschiedene Parameter studiert und deren Verträglichkeit mit der CMOS -Technologie untersucht. Die ersten Tests erfolgten auf Nickel, da hier eine im Volumen stattfindende katalytische Reaktion einsetzt. In weiteren Schritten fiel die Wahl auf Kupfer, da hier die Reaktion an der Oberfläche stattfindet und daher ein stabilerer Prozess realisiert werden konnte. Die Qualitätsprüfung der erzeugten Schichten erfolgte mittels Ramanspektrometrie. Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-3169 SN - 0949-8214 VL - 17 SP - 154 EP - 159 ER - TY - JOUR A1 - Dimitriev, O. P. A1 - Grytsenko, Kostyantyn A1 - Tolmachev, O. I. A1 - Slominskii, Yu L. A1 - Kudinova, M. A. A1 - Schrader, Sigurd T1 - Effect of Concentration on Isomerization of Rhodanine Derivatives of Merocyanine Dyes in Polar Solvents JF - Advances in Physical Chemistry N2 - Rhodanine derivatives of merocyanine dyes with residues of 1,3,3-trimethyl-3H-indole and 3-ethylbenzothiazoline have been found to possess two molecular forms in diluted solutions of polar solvents such as dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidinone. The first molecular form was observed to prevail at low concentrations of the dyes, normally up to 10−5 M. The second one prevails at higher concentrations and is displayed through a new band in the electronic absorption spectrum, which is red-shifted with respect to the absorption band of the first form. No similar effect was found for these dyes by use of nonpolar solvents or upon alkyl-substitution of the molecules at nitrogen atom in the rhodanine moiety. We assign the above two forms to different molecular isomers and the analogous spectral changes were shown to take place by light or heat influence which correspond to a typical isomerization effect for the related merocyanine dyes. It is discussed that the isomer transformation is facilitated by the increased mobility of the proton bonded to the nitrogen atom of the rhodanine moiety in the polar environment and the increased amount of dye-dye collisions. Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-5931 SN - 1687-7993 VL - 2014 ER - TY - CHAP A1 - Steglich, Patrick A1 - Villringer, Claus A1 - Dümecke, Silvio A1 - Padilla-Michel, Yazmin A1 - Casalboni, Mauro A1 - Schrader, Sigurd T1 - Silicon-On-Insulator Slot-Waveguide Design Trade-Offs T2 - Proceedings of the 3rd International Conference on Photonics, Optics and Laser Technology : vol. 2 N2 - Silicon-on-insulator slot-waveguide structures are designed and analysed numerically. We present our theoretical investigation of field confinement factors and effective nonlinear areas for different waveguide structures in order to find optimized geometrical dimensions. It is shown that a slot-waveguide with a height of 220 nm, a slot width of 180 nm and a silicon rail width of 180 nm provides a five times higher field confinement in the cladding region compared to conventional strip-waveguides which explains the high sensitivity of slotwaveguide based label-free bio-sensors. KW - slot waveguide KW - silicon-organic hybrid technology KW - optical field confinement KW - effective nonlinear area Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-20104 SP - 47 EP - 52 PB - SciTePress CY - Setúbal ER - TY - CHAP A1 - Padilla-Michel, Yazmin A1 - Lucci, Massimiliano A1 - Casalboni, Mauro A1 - Steglich, Patrick A1 - Schrader, Sigurd ED - Ribeiro, Paulo A. T1 - Mechanical Characterisation of the Four Most Used Coating Materials for Optical Fibres T2 - Proceedings of the 3rd International Conference on Photonics, Optics and Laser Technology : vol. 1 N2 - Optical multimode fibres have a wide variety of applications ranging from industrial to medical use. Therefore, even if they are just used as waveguides or sensors, it is important to characterise the whole fingerprint, including the optical and mechanical properties of such fibres. Since the stiffness/elasticity of a material could influence the optical output of a fibre due to micro-bendings, in this paper we report the calculated Young’s Modulus of acrylate, fluorinated acrylate, polyimide and silicone, which are the four most used coating materials for such optical components. The results demonstrate that Young’s Modulus does have an impact on the attenuation of propagating light along the optical fibre. However, the refractive index of the coating materials still has a significant impact on the performance of optical fibres. KW - fibre optics KW - coating material KW - Young’s Modulus KW - nanoindentation KW - attenuation Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-20063 SP - 96 EP - 102 PB - SciTePress CY - Setúbal ER - TY - JOUR A1 - Grytsenko, Kostyantyn A1 - Lozovski, Valeri A1 - Strilchuk, Galyna A1 - Schrader, Sigurd T1 - Evaluation of the Mechanism of the Gold Cluster Growth during Heating of the Composite Gold-Polytetrafluoroethylene Thin Film JF - Nanomaterials N2 - Nanocomposite films consisting of gold inclusions in the polytetrafluoroethylene (PTFE) matrix were obtained by thermal vacuum deposition. Annealing of the obtained films with different temperatures was used to measure varying of film morphologies. The dependence of optical properties of the films on their morphology was studied. It was established that absorption and profile of the nanocomposite film obtained by thermal vacuum deposition can be changed with annealing owing to the fact that different annealing temperatures lead to different average particle sizes. A method to calculate the optical properties of nanocomposite thin films with inclusions of different sizes was proposed. Thus, comparison of experimental optical spectra with the spectra obtained during the simulation enables estimating average sizes of inclusions. The calculations give the possibility of understanding morphological changes in the structures. KW - nanocomposite KW - gold KW - polytetrafluoroethylene KW - optical spectroscopy KW - microscopy KW - thin film Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-6387 SN - 2079-4991 VL - 2 IS - 4 SP - 366 EP - 378 ER - TY - JOUR A1 - Villringer, Claus A1 - Steglich, Patrick A1 - Pulwer, Silvio A1 - Schrader, Sigurd A1 - Laufer, Jan T1 - Electro-optical properties of doped polymers with high transparency in the visible wavelength range JF - Optical Materials Express N2 - The electro-optical (EO) properties of poly(methyl methacrylate) and the photopolymer poly(vinyl cinnamate) doped with varying concentrations of the EO chromophore 2-Methyl-4-nitroaniline were measured. The EO polymers were embedded in Fabry-Pérot etalons for the simultaneous determination of the Pockels and Kerr coefficients from measurements of the fringe shift induced by an external electric field. It was found that the host polymer has a significant impact on the EO performance and that the undoped host polymers exhibit a significant Pockels effect. Moreover, the Kerr effect provides a substantial contribution of 27% to the total change of the refractive index at relatively high electric field strengths of E = 91.2 MV m−1. KW - Bragg reflector KW - fiber optic coupler KW - refractive index KW - spatial light modulator KW - transparency KW - tunable filter Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-15480 VL - 11 IS - 11 SP - 3801 EP - 3811 PB - Optica Publishing Group ER - TY - JOUR A1 - Bauer, Joachim A1 - Fursenko, Oksana A1 - Heinrich, Friedhelm A1 - Gutke, Marko A1 - Kornejew, Eckhart A1 - Brödel, Oliver A1 - Dietzel, Birgit A1 - Kaltenbach, Alexander A1 - Burkhardt, Martin A1 - Edling, Matthias A1 - Steglich, Patrick A1 - Herzog, Michael A1 - Schrader, Sigurd T1 - Determination of optical constants and scattering properties of transparent polymers for use in optoelectronics JF - Optical Materials Express N2 - Knowledge of optical constants, i.e. refractive index n and extinction coefficient k, and light scattering properties of optical polymers are required to optimize micro-optics for light-emitting diodes in terms of efficiency, color properties and light distribution. We present here a model-based diagnostic approach to determine the optical properties of polymers, which should be particularly useful in the development of plastics for optical applications. Optical constants and scattering coefficients were obtained from transmission and reflection measurements in a wavelength range from UV to NIR taking into account scattering effects due to rough surfaces and volume inhomogeneity. Based on the models for the dielectric function, the molecular optical transition energies Eg, critical point energies, Urbach energies and exciton transition energies were determined. Rayleigh and Mie scattering model and van de Hulst's anomalous diffraction theory were applied to characterize scattering due to volume inhomogeneities. Scalar diffraction theory was applied to account for surface roughness scattering. Atomic force microscopy with nanomechanical characterization was used to characterize domains in size and shape and to assign optical scattering to a suitable morphological model. The combined optical and mechanical characterization help to improve the qualification of new polymer materials for optical applications. KW - diffraction theory KW - light property KW - optical constant KW - optical material KW - optical property KW - scattering theory Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-15666 VL - 12 IS - 1 SP - 204 EP - 224 PB - Optica Publishing Group ER -