Nanoscale precision of 3D polymerisation via polarisation control

TL;DR

This paper demonstrates that polarization control in femtosecond laser 3D lithography enables nanoscale precision in feature size by coupling electric field polarization with thermal gradients, supported by simulations and experiments.

Contribution

It introduces a novel method of tuning feature sizes at the nanoscale through polarization effects in femtosecond laser lithography, combining theoretical simulation and experimental validation.

Findings

Up to 20% variation in linewidth achieved experimentally.

Coupling between polarization and thermal gradients enables fine control.

Simulation confirms polarization influences feature size.

Abstract

A systematic analysis of polarization effects in a direct write femtosecond laser 3D lithography is presented. It is newly shown that coupling between linear polarization of the writing light electric field and temperature gradient can be used to fine-tune feature sizes in structuring of photoresists at a nanoscale. The vectorial Debye focusing is used to simulate polarization effects and a controlled variation up to 20% in the linewidth is shown experimentally for the identical axial extent of the polymerised features. The revealed mechanisms are relevant for a wide range of phenomena of light-matter interaction at tight focusing in laser-tweezers and in plasmonic or dielectric sub-wavelength focusing where strong light intensity and thermal gradients coexist.