# Structural color due to guided-mode resonance in silicon-on-insulator irradiated by nanosecond laser pulses

## TL;DR

Nanosecond laser pulses create structural colors on silicon wafers through optical resonance, offering a durable, non-chemical coloring method for semiconductor applications.

## Contribution

A new method for generating tunable structural colors on silicon-on-insulator wafers using laser-induced periodic surface structures and guided-mode resonance.

## Key findings

- Laser-induced structures on silicon films produce bright structural colors via guided-mode resonance.
- Color can be tuned across the visible spectrum by adjusting the silicon film thickness.
- Numerical simulations align with the observed optical properties of the coloration.

## Abstract

We demonstrate structural color generation in silicon-on-insulator wafers using nanosecond laser irradiation. Laser-induced periodic surface structures on the thin Si film act as grating couplers, enabling optical resonances that produce bright, spectrally selective structural colors at visible wavelengths. The mechanism combines grating-mediated waveguide coupling with Fabry-Perot spectral filtering, yielding optical characteristics resembling guided-mode resonance. The central wavelength is tunable across the visible spectrum by varying Si film thickness (50–70 nm range), with measured samples exhibiting green coloration at 55 nm and red at 70 nm thickness. Numerical simulations qualitatively reproduce the observed optical properties. This non-chemical, non-fading coloration offers potential applications in secure marking and process control for semiconductor manufacturing.

Nanosecond laser-induced LIPSS enable guided-mode resonance structural color on SOI wafers by combining grating coupling and Fabry-Perot filtering for angularly stable non-chemical, maskless coloration in semiconductor security and process control