Rapid Optical Erasure of Surface Relief and Bulk Birefringence Gratings in Azo-Polymer Thin Films

摘要

We report on light induced reversible structuring of azobenzene containing polymer films under dynamic changes of the local distribution of the electrical field in the irradiating interference pattern. This is achieved utilizing a homemade setup which consists of three parts: a two-beam interference lithography for topography structuring, an atomic force microscope for in-situ recording (during irradiation) of surface morphology and a diffraction efficiency setup which enables to obtain information about the birefringence grating development simultaneously. Introducing a phase delay between the two interfering beams results in a shift of the whole interference pattern along the sample plane and subsequent change in topographical grating. In this way one can reversibly structure the surface topography in a controlled way and quite fast. On the other hand, this allows to erase the surface grating by just performing half period shift. Combining this method with a single beam exposure creates a very efficient way of completely erasing the birefringence and surface grating.