High spatial frequency periodic structures induced on ferric ion-doped Polyvinyl Pyrrolidone film by femtosecond laser pulses

TL;DR

This study demonstrates the formation of high spatial frequency nano-gratings on ferric ion-doped PVP films using femtosecond laser pulses, revealing controllable parameters and potential applications in biophotonics and nanophotonics.

Contribution

First demonstration of femtosecond laser-induced nano-gratings on ferric ion-doped PVP films with tunable parameters and potential for advanced photonic applications.

Findings

Nano-gratings with 60-100nm period were induced.

Gratings' orientation is perpendicular to laser polarization.

Formation is influenced by laser energy and scanning speed.

Abstract

Utilizing continues-wave or pulsed laser to induce nano-structures on various material surfaces is one significant method in nano-fabrication technology. In this report, we investigate the formation of high spatial frequency periodic structures on Polyvinyl Pyrrolidone (PVP) film by a linearly polarized femtosecond laser. Ferric (Fe) ions are introduced into the film to improve the photosensitivity. Regular nano-gratings with spatial periods at the range of 60-100nm, which are about one tenth of the irradiating wavelength, can be induced. The period direction of the nano-gratings is perpendicular to the polarization of the femtosecond laser. By tuning the laser energy and scanning speed, we find that the nano-gratings can be formed in a wide range of experimental parameters. As high laser energy can excite not only metals, but also semiconductors and polymers, we believe the formation of the nano-gratings is due to the interaction between the incident femtosecond laser and surface plasmons. The laser processable PVP-based materials and the induced nano-gratings will have potential applications in biophotonics and nanophotonics.