Selection of absorptive materials for non-reflective wire grid polarizers

Abstract

Wire grid polarizers often have reflective characteristics, such that some incident light is transmitted through the polarizer, while the rest is reflected. For some applications, such as anti-reflective films in OLEDs, non-reflective (or absorptive) wire grid polarizers are necessary; these can be realized by the deposition of an absorptive material on the nanoscale metal wire grid. However, because this deposited absorptive layer can severely affect the polarization characteristics, its material must be selected carefully. The polarization characteristics of a given nanowire grid polarizer can be simulated using rigorous coupled-wave analysis (RCWA). In this study, several types of metal oxides and nitrides were tested as candidate materials for the absorptive layer of a non-reflective polarizer. Nanopatterned double layers with absorptive and reflective functions were modeled using RCWA. Simulations were conducted for various pattern widths, depths, and periodicities. CuO and Fe3O4 showed optimal polarization characteristics among the simulated absorptive layers. Simulations indicated that the performance of non-reflective wire grid polarizers could be enhanced using CuO or Fe3O4. The design of absorptive polarizers was fully characterized by simulation for future experimental research.