Precise regulation of color rendering and multidimensional optical encryption enabled by electrically tunable all-dielectric grating devices

Abstract

Secure optical encryption and anti-counterfeiting technologies require platforms that are both physically reconfigurable and algorithmically robust. While electrically tunable structural color systems offer advantages like reversibility and high chromatic purity, achieving precise multi-parameter modulation and integrating them with advanced digital cryptographic methods remain a challenge. Herein, we report a novel multidimensional electro-optic encryption platform by integrating MgO-doped polymer-dispersed cholesteric liquid crystals (MgO-PDCLC) with all-dielectric nanograting structures. The key novelty of this work lies in the holistic synergy of material, device, and algorithmic innovations: Firstly, MgO doping critically enhances the electro-optic response, lowering operational voltage. Secondly, the bilayer architecture functions as a voltage-gated optical switch, dynamically concealing or revealing structural color patterns. The device's optical responses under variable voltage, incident angle, and polarization were comprehensively characterized through finite-difference time-domain (FDTD) simulations and experimental validations. A highly accurate nonlinear regression model (R² > 0.9) was developed to quantitatively predict structural color parameters, enabling precise control. Utilizing these tunable spectral features, we propose a groundbreaking encryption scheme that seamlessly bridges physical photonic encoding and algorithmic security by coupling structural color outputs with Rivest Shamir Adleman (RSA) public-key cryptography. A dedicated software platform was implemented to realize this dual-layer encryption, enabling an information capacity up to 10ⁿ, where encryption is physically concealed without power. This work establishes a versatile framework that paves the way for next-generation secure displays, smart labeling, and anti-counterfeiting applications. Keywords: Structural color; Electro-optic tuning; Dielectric grating; Multidimensional coding; Anti-counterfeiting; Optical encryption.