# Time-programmable coloration via 3D metastructures for optical encryption

## TL;DR

This paper introduces a new optical encryption method using 3D structures that can change colors and self-destruct after being read, offering high security for sensitive information.

## Contribution

The novel approach introduces time-programmable coloration encryption with self-destruction capabilities using 3D metastructures and refractive-index modulation.

## Key findings

- A 3D metastructure enables continuous spectral tuning for optical encryption.
- Capillary forces induce irreversible self-destruction of the encryption carrier.
- The method demonstrates 'burn after reading' functionality in a single device.

## Abstract

Optical information encryption technology, with its advantages such as high-dimensional encryption characteristics and resistance to quantum computing decryption, has demonstrated unique application value in fields like military, communication, and commercial confidential information protection. However, current optical encryption technologies still face challenges such as limited information capacity and security protection bottlenecks due to discrete state switching mechanisms, as well as potential risks of information residual leakage. Here, we propose a continuously tunable time-programmable coloration encryption strategy enabled by three-dimensional metastructures, featuring wide color gamut spectral continuous tuning through the control of the environmental refractive index. Moreover, by innovatively inducing irreversible collapse of nanopillars through capillary forces, the encryption carrier is endowed with physical self-destruction characteristics, thereby enabling “burn after reading” of the encrypted information. As a proof of concept, we demonstrated time-programmable information encryption and self-destruction after reading within a single device, enabled by continuous spectral modulation across the visible wavelength range. This technology provides an innovative solution for dynamic response in information encryption and secure information destruction, showing significant application potential in high-security scenarios such as military confidential transmissions and high-end commercial anti-counterfeiting.

A continuously tunable time-programmable 3D metastructure coloration encryption approach with wide-gamut spectral control via refractive-index modulation and capillary-driven self-destruction is presented for high-capacity secure information encryption.