Recently, tunable color filters have been desirable for various applications such as tunable colored glasses, camouflage materials, smart labels, smart windows, and dynamic displays. Herein, we present an optical rotation-based color tuning (ORCT) method, which is a cost-effective and non-destructive 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 colored glasses are demonstrated to filter out unexpected light sources and provide better visibility. Our ORCT technology can be a cornerstone in potential color variation applications.
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