Laser-Scrawled Random Plasmonic Metasurface in Nanoseconds for Physical Unclonable Functions

TL;DR

This paper presents a rapid, scalable laser scribing method to create unique, irreproducible plasmonic metasurfaces for optical security, achieving high capacity and stability in physical unclonable functions.

Contribution

It introduces a nanosecond laser scribing technique for one-step fabrication of random plasmonic metasurfaces, enabling fast, chemical-free production of optical PUFs with high encoding capacity.

Findings

Achieved ~28000 bits capacity per PUF.

Demonstrated high uniqueness and uniformity in keys.

Ensured environmental stability and resistance to reverse nanofabrication.

Abstract

Randomness in optical systems emerges as a powerful resource for generating complex, non-deterministic light-matter interactions. In particular, random plasmonic metasurfaces harness nanoscale disorder to produce unique and irreproducible optical responses, positioning them as an ideal platform for physical unclonable function in secure optical authentication. However, realizing such random metasurfaces in a rapid, scalable, and chemical-free manner for optical PUFs remains challenging. Here, we introduce a nanosecond pulsed laser scribing method for one-step fabrication of a robust random plasmonic metasurface physical unclonable function. By delivering spatially localized, ultrafast energy bursts, this technique harnesses naturally occurring instability to generate stochastic plasmonic nanostructures in nanoseconds. The unique plasmonic metasurfaces are effectively transformed into a macroscopic, non-replicable optical fingerprint via morphology-dependent resonance at the nanoscale, enabling low-cost and fast readout. Leveraging the wavelength-selective plasmonic response, we present a multidimensional multiplexing strategy that expands the challenge response pairs space and encoding capacity by 5-fold via topography and RGB multiplexing. The resulting plasmonic keys exhibit good bit uniformity (average: 0.500), high uniqueness (inter-Hamming distance: 0.499), and large capacity (~28000 bits per PUF), with strong environmental stability and resistance to reverse nanofabrication. This work demonstrates how fast laser induced stochasticity can be rationally harnessed and engineered for optical PUFs, opening pathways toward disorder-enabled photonic devices.