Stress birefringence patterning in photopolymer induced by structured illumination

► Demonstration of birefringence photopatterning in photocrosslinkable materials. ► Distributed mechanical stresses are induced by inhomogeneous photopolymerization. ► Distribution of stresses leads to birefringence patterning. We report on the stress birefringence distribution induced by the photopatterning of a multifunctional crosslinkable acrylate monomer sensitized in the visible range. The patterning of this material, prepared in a glass cell of a few tens of microns thickness, is obtained through illumination in a two steps process. The first step is performed using an illumination pattern with a high contrast and a low spatial frequency. The second one is a uniform illumination. The discrepancies in the shrinkage experimented by the material leads to the apparition of patterned stress birefringence revealed through polarimetry and diffraction measurements.