@article{KarageorgievNeherSchulzetal.2005, author = {Karageorgiev, Peter and Neher, Dieter and Schulz, Burkhard and Stiller, Burkhard and Pietsch, Ullrich and Giersig, Michael and Brehmer, Ludwig}, title = {From anisotropic photo-fluidity towards nanomanipulation in the optical near-field}, issn = {1476-1122}, year = {2005}, abstract = {An increase in random molecular vibrations of a solid owing to heating above the melting point leads to a decrease in its long-range order and a loss of structural symmetry. Therefore conventional liquids are isotropic media. Here we report on a light-induced isothermal transition of a polymer film from an isotropic solid to an anisotropic liquid state in which the degree of mechanical anisotropy can be controlled by light. Whereas during irradiation by circular polarized light the film behaves as an isotropic viscoelastic fluid, it shows considerable fluidity only in the direction parallel to the light field vector under linear polarized light. The fluidization phenomenon is related to photoinduced motion of azobenzene-functionalized molecular units, which can be effectively activated only when their transition dipole moments are oriented close to the direction of the light polarization. We also describe here how the photofluidization allows nanoscopic elements of matter to be precisely manipulated}, language = {en} } @article{BochenkovKarageorgievBrehmeretal.2004, author = {Bochenkov, V. and Karageorgiev, Peter and Brehmer, Ludwig and Sergeev, G. B.}, title = {Quenched growth of nanostructured lead thin films on insulating substrates}, issn = {0040-6090}, year = {2004}, abstract = {Lead island films were obtained via vacuum vapor deposition on glass and ceramic substrates at 80 K. Electrical conductance was measured during vapor condensation and further annealing of the film up to room temperature. The resistance behavior during film formation and atomic force microscopy of annealed films were used as information sources about their structure. A model for the quenched growth, based on ballistic aggregation theory, was proposed. The nanostructure, responsible for chemiresistive properties of thin lead films and the mechanism of sensor response are discussed. (C) 2003 Elsevier B.V. All rights reserved}, language = {en} } @article{StillerKarageorgievBuchsteineretal.2003, author = {Stiller, Burkhard and Karageorgiev, Peter and Buchsteiner, Andrea and Geue, Thomas and Henneberg, Oliver and Brehmer, Ludwig and Natansohn, Almeria and Hollricher, Olga}, title = {Using light as a tool : optically Induced mass transport generated in Near-Fields}, issn = {0038-7355 -}, year = {2003}, language = {en} } @article{KarageorgievStillerPrescheretal.2000, author = {Karageorgiev, Peter and Stiller, Burkhard and Prescher, Dietrich and Dietzel, Birgit and Schulz, Burkhard and Brehmer, Ludwig}, title = {Modification of the surface potential of azobenzene-containing langmuir-blodgett films in the near field of a scanning kelvin microscope tip by irradiation}, year = {2000}, language = {en} } @article{StillerKarageorgievPerezetal.2000, author = {Stiller, Burkhard and Karageorgiev, Peter and Perez, E. and Valez, M. and Reiche, J{\"u}rgen and Prescher, Dietrich and Dietzel, Birgit and Brehmer, Ludwig}, title = {Scanning kelvin microscopy as a tool for visualisation of optically induced molecular switching in azobenzene self assembling films}, issn = {0142-2421}, year = {2000}, language = {en} } @article{StillerKoepnickMuzikanteetal.1999, author = {Stiller, Burkhard and K{\"o}pnick, Thomas and Muzikante, I. and Neilands, O. and Utinans, M. and Dubrovich, O. and Karageorgiev, Peter and Brehmer, Ludwig}, title = {Optically induced switching effect of polymer containing indandione-1,3-pyridinium betaine side chains}, issn = {0378-2271}, year = {1999}, language = {en} } @article{StillerKarageorgievGeueetal.2004, author = {Stiller, Burkhard and Karageorgiev, Peter and Geue, Thomas and Morawetz, Knut and Saphiannikova, Marina and Mechau, Norman and Neher, Dieter}, title = {Optically induced mass transport studied by scanning near-field optical- and atomic force microscopy}, issn = {0204-3467}, year = {2004}, abstract = {Some functionalised thin organic films show a very unusual property, namely the light induced material transport. This effect enables to generate three-dimensional structures on surfaces of azobenzene containing films only caused by special optical excitation. The physical mechanisms underlying this phenomenon have not yet been fully understood, and in addition, the dimensions of structures created in that way are macroscopic because of the optical techniques and the wavelength of the used light. In order to gain deeper insight into the physical fundamentals of this phenomenon and to open possibilities for applications it is necessary to create and study structures not only in a macroscopic but also in nanometer range. We first report about experiments to generate optically induced nano structures even down to 100 nm size. The optical stimulation was therefore made by a Scanning Near-field Optical Microscope (SNOM). Secondly, physical conditions inside optically generated surface relief gratings were studied by measuring mechanical properties with high lateral resolution via pulse force mode and force distance curves of an AFM}, language = {en} }