Single shot and highly parallel photopolymerisation with complex light patterns generated by diffrative optical elements

摘要

Photopolymerisation by computer controlled scanning of a focused laser beam is a powerful method to build structures of arbitrary complexity with submicrometer resolution. The procedure has already proven effective to produce complex structures that can be manipulated in optical tweezers. These micromechanical systems consist of static and moving parts and are expected to be building blocks of highly capable microfluidic systems. To enhance the efficiency of structure building, we developed single shot photopolymerisation. Instead of complicated multidimensional scanning the whole structure is generated simultaneously with special diffractive patterns. We experimented with fixed diffractive optical elements, kinoforms, and Spatial Light Modulators (SLMs). By using kinoforms, cross shaped structures were produced in single shots as an illustration. These propellers were produced about an order of magnitude faster than by simple scanning, and can be rotated by optical tweezer. The complexity of the structure depends on the quality of the kinoform and the available laser power. With the concerted movement of the appropriately chosen basic pattern and the sample, the building of more complicated structures can also be greatly accelerated due to the parallel nature of the polymerisation. The possibilities of photopolymerisation using SLM were also explored: the added flexibility using the programmable device is demonstrated.