Abstract
Physically transient optics, a form of optics that can physically disappear with precisely controlled degradation behaviors, has widespread applications including information security, drug release, and degradable implants. Here, a set of silk-based programmable vanishing, biologically functional, multichromatic diffractive optical elements (MC-DOEs) is reported. Silk proteins produced by silkworms and spiders are mechanically robust, biocompatible, biodegradable, and importantly, optically transparent, which open up new opportunities for a set of fully degradable transient optical devices with no need of metallic or semiconductor components. Compared with monochromatic DOEs, MC-DOEs carry out richer information for more practical applications such as encryption and decryption of multilevel information, quantitative sensing/monitoring of chemical/biological cascade reactions, and effective treatment of infections caused by multiple pathogens.