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Polymer surface relief structures caused by light-driven diffusion

: Kulikovska, O.; Gharagozloo-Hubmann, K.; Stumpe, J.


Meerholz, K.:
Organic Photorefractive and Photosensitive Materials for Holographic Applications
Bellingham, WA: SPIE, 2002 (Proceedings of SPIE 4802)
ISBN: 0-8194-4570-3
Organic Photofefractive and Photosensitive Materials for Holographic Applications <2002, Seattle>
Conference Paper
Fraunhofer IAP ()

Two amorphous side-chain copolymethacrylates containing 60% azobenzene chromophores (PII, PIV) were irradiated homogeneously with a linear polarized Ar+ ion laser beam at 488 nm. From polarized UV/VIS spectra the maximum of the photoinduced dichroism was calculated (dPII=0.25, dPIV=0.35). No intensity dependence of this values was notified. PIV was irradiated under holographic conditions with a grating period of 30 m. Two types of polarization gratings, circular orthogonal and linear orthogonal ones were inscribed. Using a microscope spectrometer polarized UV/VIS spectra were measured within the grating period with a lateral resolution of about 2 m. The induced local dichroism was measured and the different modulation of the molecular orientation in the recorded gratings was confirmed by this direct experiment. PII was used to monitor the grows up stages of the surface relief grating, starting from the molecular photoorientation until the surface deformation. Parallel t o the online observed diffraction efficiency, the offline surface profile measurements were done by AFM. The details of surface topography and the reversibility of the process are discussed and an interesting possibility of the surface structuring is demonstrated.