A new fabrication method for nano-gratings based on the high flexibility of PDMS

A new method for simple and low-cost fabrication of nano-grating structures is reported in this paper. First, microscale grating structures on the master mold are replicated into Polydimethylsiloxane(PDMS), which serves as an intermediate, negative mold, by a conventional soft lithography process. The PDMS negative mold was then stretched along the direction of the grating lines to reduce the period of grating. Last, transfer the grating pattern from the PDMS membrane to PMMA. Nano-grating can be fabricated on polymethylmethacrylate(PMMA) by repeating the steps for several times. The grating has been tested and performs the width of 820 nm. The technology, utilizing the high elasticity of PDMS and the nano-molding technology, can be used to fabricate nano-gratings in low-cost and no expensive or high precision equipment. Because of the excellent replication property of PDMS molds, a large number of gratings can be made with a single master mold. The nano-gratings can be widely used in the optical measurement, integrated optics, optical information processing and other fields.