Nearly Polarization-Independent Angular Filters Consisting of One-Dimensional Photonic Crystals Realized in the Visible Region

We present an experimental study of one-dimensional photonic crystal based angular filters. The filters have the feature of the nearly polarization-independent angular response, which is desired in many application scenarios. A transmission angular filter with an alternate stack of SiO 2 /TiO 2 layers on a SiO 2 substrate is realized in the visible region through the detailed tolerance study. The experimental result agrees with the numerical result obtained by the transfer matrix method. The effectiveness of the angular selectivity is experimentally verified in an optical communication system. In addition, we show that a reflection angular filter, which has reflection around the normal direction and transmission for some of the other oblique angles, can be implemented in the visible region.