Optical Rotation‐Based Tunable Color Filter Using Chiral Photonic Crystal

Abstract Recently, tunable color filters have been desirable for various applications such as tunable colored glasses, camouflage materials, smart labels, smart windows, and dynamic displays. An optical rotation‐based color tuning (ORCT) method is presented here, which is a cost‐effective and nondestructive way to provide a wide range of color tunability using a controlled cholesteric liquid crystal (CLC) as a chiral photonic crystal and two polarizers. Moreover, the color range of the ORCT can be manipulated by engineered optical rotation of the CLC film, which is verified by numerical calculations and experiments. As a proof of concept, tunable color filters are demonstrated to attenuate unexpected light sources and provide better visibility. We believe that our ORCT technology can be a cornerstone in potential color variation applications.