Fabrication of micropolarizer array for visible polarization imaging

A method for fabricating a thin film micropolarizer array using electron beam lithography and inductively coupled plasma-reactive ion etching (ICP-RIE) is presented. In this work, a 100 nm aluminum layer was sputtered on the substrate via magnetron sputtering, and a 140 nm layer of polymethyl methacrylate (PMMA) photoresist was spin-coated at 4000 rpm for 50 s, and prebaked at 180 °C for 120 s. The grating patterns were transferred from the photoresist to the aluminum layer using ICP-RIE. The micropolarizer array was fabricated with many aluminum wire grid polarizers, whose period range was from 140 nm to 200 nm, and the extinction ratios of the different periods were obtained in the visible spectrum. The optical performance measurement has shown that this work provides a feasible method to fabricate wire grid polarizer arrays.