@article{KsianzouVelagapudiGrimmetal.2006, author = {Ksianzou, Viachaslau and Velagapudi, R. K. and Grimm, Bernd and Schrader, Sigurd}, title = {Polarization-dependent optical characterization of poly(phenylquinoxaline) thin films}, series = {Journal of Applied Physics}, volume = {100}, journal = {Journal of Applied Physics}, number = {6}, issn = {1089-7550}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-9761}, year = {2006}, abstract = {Linear optical properties of two types of poly(phenylquinoxaline) (PPQ) are studied by multiwavelength prism coupling technique and optical absorption spectroscopy. Surface roughness measurements are done using atomic force microscopy. PPQs form smooth films of high optical quality having refractive indices above 1.7 in the visible and near infrared spectral ranges. Enhanced birefringence of Δn∼0.04Δn∼0.04 has been observed in both PPQ films prepared by spin coating. Sellmeier coefficients are derived for the wavelength range starting from 0.532to1.064μm0.532to1.064μm for both TE and TM polarizations. Quantum chemical calculations both on the semiempirical and on the ab initio level are carried out in order to calculate the first-order molecular polarizability tensors of the polymer repeat units. From the obtained tensor elements, theoretical values for both the average refractive indices and the maximum expectable birefringence are calculated. Based on these values a more detailed interpretation of the experimental findings is carried out. The dispersion of refractive index is quantified by the value of Abbe's constant (νd)(νd). In our case the value νd≈11νd≈11 indicates high dispersion in the visible spectral range. The imaginary part kk of the complex refractive index n∗=n-ikn*=n-ik reaches values of k⩽10-3k⩽10-3 in the wavelength range from 0.5to1μm0.5to1μm.}, language = {en} } @inproceedings{GrytsenkoDoroshenkoKolomzarovetal.2008, author = {Grytsenko, Kostyantyn and Doroshenko, T. and Kolomzarov, Yurii and Prokopets, Vadym M. and Fedoriak, O. and Zelinski, R. and Lytvyn, Oksana and Prescher, Dietrich and Grimm, Bernd and Ksianzou, Viachaslau and Schrader, Sigurd and Tolmachev, O. I. and Slominskii, Yu L. and Kurdiukov, V. and Smirnova, G.}, title = {Research on the growth of dye film in vacuum in situ}, publisher = {Society of Photo-Optical Instrumentation Engineers (SPIE)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15206}, pages = {318 -- 323}, year = {2008}, abstract = {Organic film deposition in vacuum is fast developing scientific and industrial domain. We developed installation for deposition of organic films equipped with optical spectrometer for measurements in situ. We are developing new dyes aimed for application in waveguide sensor, nonlinear optics and studying film organisation during deposition. Fluorinated azo-dyes and azomethine dyes were synthesized at University of Applied Sciences Wildau and at the Institute of Organic Chemistry, Kyiv. Compounds were evaporated at a pressure of 10-3 Pa using resistive heated crucible. Glass and glass covered with polytetrafluoroethylene (PTFE) film are used as substrates. The films were studied with Polytec and StellarNet spectrometers and an atomic force microscope. Optical spectra of the dye films revealed, that some compounds were decomposed during evaporation. Several kinds of dyes were evaporated and deposited without decomposition. Some deposited films formed H-aggregates and other types of aggregates. AFM images of dye films showed that their morphology depends on the chemical structure of the compounds and on the nature of the substrate on which the film was grown.}, language = {en} } @inproceedings{MeisterSchwedaDziedzinaetal.2010, author = {Meister, Stefan and Schweda, Dawid and Dziedzina, Marcus and Al-Saadi, Aws and Franke, B{\"u}lent A. and Scharfenorth, Chris and Grimm, Bernd and Dufft, Daniela and Schrader, Sigurd and Eichler, Hans J.}, title = {Single cavity filters on end-faces of optical fibers}, publisher = {Society of Photo-Optical Instrumentation Engineers (SPIE)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-15214}, pages = {253 -- 261}, year = {2010}, abstract = {We have developed thin film Fabry-Perot filters directly coated on optical fibers to archive a high level of integration with a reduction of optical elements. Such band-pass filters can be used in fiber optical sensor systems, and for fiber communication, e.g. CWDM applications. The filters cavities consist of a single spacer and two dielectric mirrors. The dielectric mirrors are deposited by PVD directly on end-faces of single-mode optical fibers. Dielectric as well as polymeric materials were applied as the spacer layer. Polymeric spacer layers were deposited by dip coating. The influence of the mirror reflectivity on the transmission band of the Fabry-Perot filters was investigated. Furthermore, the optical performance of filters with first order (λ/2) as well as higher order spacers was analyzed. The experimental results are compared with numerical analysis of Fabry-Perot cavities on the end-face of cylindrical waveguides. The spectral characteristic of the filters are calculated using a software solving Maxwell´s equations by a FDTD method. The layer design of the filters and the deposition process were optimized for maximum transmission and narrow bandwidth of the transmission peak. Passive band-pass filters on fiber end-faces were designed, fabricated and characterized for transmission wavelengths of 945 nm, 1300 nm, as well as 1550 nm. Bandwidths as narrow as 1 nm could be achieved for 945 nm.}, language = {en} }