Enhancing Color Gamut with Wavelength‐Selective Polarization Modulation in Chiral Liquid Crystals

Abstract Dichroic dye‐doped liquid crystal (LC) films are extensively developed to mimic the polarization‐dependent coloration found in nature, demonstrating potential applications in various optical devices, like displays. However, despite their remarkable optical anisotropy and functional potential, achieving precise coloration, especially green hues, in dichroic dye‐based films remains challenging due to the inherently broad absorption bands of the dyes. In this study, a straightforward and effective platform is proposed to extend the color gamut of dichroic dye‐doped LC films by utilizing cholesteric liquid crystals (CLCs) as wavelength‐selective polarization modulators. CLCs induce continuous optical rotation across the visible spectrum, enabling modulation of the polarization state of transmitted light. By systematically analyzing the optical properties of CLC, red, and cyan dichroic film‐based trilayer systems, the study demonstrates that simultaneous wavelength‐ and polarization‐selective absorption significantly extends the color gamut beyond that of conventional dichroic films. The findings indicate that the strategic positioning and alignment direction of dichroic films allow for precise control over transmission colors, making it possible to achieve previously unattainable green hues and a wider range of color variations.