Laser-induced dewetting destabilizes a continuous thin film with light, causing it to retract into nanoscale, island-like structures. The technique is faster and more precise than thermal dewetting, making it potentially useful for patterning metallic films. However, controlling the size and distribution of the resulting structures remains difficult, while unwanted dewetting can reduce the lifetime of coatings and impair nanoscale devices.
A study published in the IEEE Journal of Selected Topics in Quantum Electronics examined whether engineered optical environments could provide greater control over the process. The researchers created four samples with the same chemical composition but different optical structures beneath a 10-nanometer gold film. They changed the thickness of the underlying silica and gold layers to modify the optical environment.
Two samples displayed the expected solid-state dewetting behavior. The other two produced previously unreported features, including wide distributions of particle sizes ranging from the nanoscale to the microscale, as well as complex spatial patterns.
The results suggest that nonlocal optical effects influence dewetting alongside thermal, capillary and fluid-dynamic effects. Finite-element simulations ruled out local variations in the electric field as the explanation for the observed behavior.
The researchers say that engineering the underlying optical cavity could provide a way to control the morphologies formed during dewetting. They also indicate that the approach could offer additional flexibility in managing dewetting dynamics and potentially help limit laser-induced damage in applications where the process is undesirable.
The study, “Laser-Induced Dewetting of Gold Thin Films on Optically Engineered Substrates,” was authored by Elias A. Anwar and colleagues. Its DOI is 10.1109/jstqe.2026.3665139.
Sources: Phys.org.