Photonic printing through the orientational tuning of photonic structures and its application to anticounterfeiting labels.

A novel photonic printing technique based on the orientational tuning of photonic structures is developed. In the printing process, the θ-contrast pattern is produced by magnetic alignment, orientational tuning, and lithographical photopolymerization. Labels printed with two mirror-symmetric or multiple axially symmetric photonic orientations show a switchable color distribution or dynamic color halo when the angle of incident light changes or samples are tilted. This printing method is capable of fabricating colorimetric or invisible codes, which can be decoded by visual observation or a spectrometer.