Direct-write laser-induced self-organization and metallization beyond the focal volume in tellurite glass

TL;DR

This paper demonstrates a laser-induced self-organization process in tellurite glass that creates periodic nanopatterns and induces metallization, extending beyond the laser focus and involving phase change and elemental redistribution.

Contribution

It reveals a novel self-organization and metallization mechanism in tellurite glass driven by femtosecond laser irradiation, including phase change and nanostructure formation beyond the focal volume.

Findings

Formation of periodic nanopatterns perpendicular to laser polarization

Phase change from glassy tellurium-oxide to crystalline tellurium

Self-organization reinforced by metallization in open air

Abstract

We report on a self-organized process initiated on a potassium-tungsten-tellurite glass surface under repetitive femtosecond laser irradiation in a regime where cumulative effects lead to a localized melting. Specifically, we show that self-organized periodic patterns consisting of parallel nanoplanes perpendicular to the laser polarization are forming and extending beyond the zone under direct laser exposure. Examination of the modified regions revealed a phase change from a glassy tellurium-oxide to a crystalline elemental tellurium. In addition, we observe that this self-organization process, associated with elemental redistribution and deoxygenation, is triggered by the optical-field strength. We suggest that early self-organized nanostructures formed by a local-field enhancement is subsequently reinforced by a metallization event in an open-air atmosphere.