Rotating twisted templates for imprinting polarization gratings with a sub- to dozen-micron period.

In this Letter, we report and experimentally demonstrate what is to our knowledge a novel scheme for imprinting polarization gratings (PGs) with a pair of templates. Compared with the traditional method that a single template can only imprint PG with a single period, cascading two templates can control the period of imprinted PG at will. However, the low diffraction efficiency is inevitably caused by cascading two templates. Therefore, a rigorous coupled wave analysis (RCWA) is adopted to design a multi-twisted template to address this challenge. As a proof of concept, two multi-twisted templates with a period of 1.6 μm were fabricated, and PGs with a large period range from 0.4 to 48.6 μm were successfully imprinted. The proposed scheme is expected to enable rapid, robust, and high-quality mass production of beam steering, large-angle deflectors, and diffractive optical couplers.