Direct laser printing of high-resolution physically unclonable anti-counterfeit labels

TL;DR

This paper demonstrates a scalable femtosecond laser printing method to create high-resolution, durable, and unclonable anti-counterfeit labels with unique optical signatures for secure product authentication.

Contribution

It introduces a simple, scalable femtosecond laser printing technique to produce high-resolution PUF labels with large encoding capacity and spectrally distinct optical signals.

Findings

Achieved 12500 dpi resolution in laser-printed PUF labels.

Created labels with an encoding capacity of 10^895.

Produced unique, unclonable optical scattering signatures for security.

Abstract

Security labels combining facile structural color readout and physically unclonable one-way function (PUF) approach provide promising strategy for fighting against forgery of marketable products. Here, we justify direct femtosecond-laser printing, a simple and scalable technology, for fabrication of high-resolution (12500 dots per inch) and durable PUF labels with a substantially large encoding capacity of 10$^{895}$ and a simple spectroscopy-free optical signal readout. The proposed tags are comprised of laser-printed plasmonic nanostructures exhibiting unique light scattering behavior and unclonable 3D geometry. Uncontrollable stochastic variation of the nanostructure geometry in the process of their spot-by-spot printing results in random and broadband variation of the scattering color of each laser printed "pixel", making laser-printed patterns unique and suitable for PUF labeling.