Viscoplastic photoalignment modeling of azopolymer deformation under structured light

A unique property of side-chain azopolymers is their ability to convert structured light irradiation into a well-defined stress field. This is created by the alignment and stretching of the polymer backbones along the light polarization, which acts as a nematic director. Elliptically polarized light causes a biaxial orientation of azopolymers and thus a biaxial deformation. Using viscoplastic photoalignment modeling, we show that excellent agreement with experimentally observed reshaping of azopolymer microobjects can be achieved. 3D light fields such as highly focused Gaussian beams or various q-plate patterns are implemented in ANSYS either analytically or by mapping their intensity, polarization and ellipticity at each material point.