Interdependence of volume shrinkage, spatial frequency and mass transfer in relief gratings fabricated with self-processing photopolymers

Local changes in thickness occurring upon controlled exposure to light of photopolymers capable of storing optical information were investigated. The image that developed as a relief in the photosensitive layer exhibited a completely self-processing character because it did not require any chemical post-treatment. Special attention was given to the effect of the gradient of chemical composition, the volume shrinkage, the gradient of surface free energy leading to mass transfer during the generation of low frequency relief gratings. This imaging technique provides a high flexibility as regards height and shape of the generated relief. It allows fabrication of both diffractive and refractive optical elements (such as gratings, microlenses, computer-generated holograms...) that come increasingly into prominence as the micro-opto-electro-mechanical field expands.