Polychromatic Circularly Polarized Luminescence Enhanced Multi-Dimensional Encryption

Abstract

Optical encryption exploits the high-dimensionality of light for physical-layer security, offering inherent resistance to algorithmic attacks and a powerful alternative to electronic methods. To meet growing demands in secure logistics, anti-counterfeiting, and hardware authentication, a dynamic platform for multiple optical parameter control is essential to fully harness light's potential for advanced encryption. Here, we demonstrate such a platform using a thermally tuned, luminophore-doped chiral photonic crystal. This medium provides dynamic, reversible selectivity in both wavelength and circular polarization, governed by the match between the photonic bandgap and the fluorescence peak: a match yields strong circularly polarized luminescence with a high dissymmetry factor (g_lum), while a mismatch results reduced g_lum. Further, geometric phase modulation allows arbitrary holograms to be encoded into the cholesteric liquid crystal alignment, and laser direct writing (LDW) enables customizable amplitude patterns. We integrate the polarization, wavelength, phase, and amplitude dimensions into a single encryption scheme. The decryption key is embedded within the hologram. Only the correct thermal and illumination keys yield a unique amplitude, spin, and fluorescence combination, further compressed into a single binary code. This work establishes a versatile strategy for high-dimensional optical encryption, significantly upgrading the security frontier for information and privacy protection.