Light Filtering Using Sub-wavelength Periodic Structures on Polymer Material

In this work, the diffractive capability of nano-scale gratings fabricated on transparent substrates is investigated. Nano-hole arrays of 9 to 20 mm(2) with 450 nm, 550 nm and 650 nm periodicities were milled on 5 nm-thick chromium coated sheet of polyethylene terephthalate (PET) substrates using a focused ion beam (FIB) to create periodicity-dependent diffraction patterns. Based on the method with which the diffraction pattern was measured a new technology is proposed in which the optical signals are used to encode information.