@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}, doi = {10.1063/1.2349471}, 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} }