Supramolecular azopolymer thin films are a promising material for the one-step fabrication of optical microstructures. Here we report the application of these materials to the fabrication of micrograting surface arrays, also known as dotmatrix holograms. The films were fabricated using commercially available azobenzene and polymeric components and were spin-coated on glass. The gratings were photopatterned using two-beam interference at 488 nm with 2.5 mW optical power and exposure times under 10 s. The gratings appear immediately, require no post-exposure processing, and their amplitude can be precisely controlled via exposure time. This was exploited to create two-dimensional dot-matrix arrays by mapping gray-scale images to exposure time. Individual surface relief gratings were 50 μm in diameter, with a sinusoidal amplitude up to 600 nm. The dot spacing was controlled by mechanically translating the film between exposures, with resolutions up to 800 dpi possible. The dot matrix structures are stable in ambient conditions and can be replicated using nanoimprint lithography.
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