Sub-wavelength Lithography of Complex 2D and 3D Nanostructures without Dyes

TL;DR

This paper introduces a cost-effective, dye-free method for high-resolution 2D and 3D nanostructure lithography using a large amount of photoinitiator in photopolymers, avoiding toxic dyes and enabling rapid fabrication.

Contribution

A novel one-step technique that achieves sub-wavelength nanostructures without dyes by leveraging the two-photon absorption of a large amount of photoinitiator in commercial photopolymers.

Findings

Successfully fabricated complex 2D and 3D patterns with sub-micron resolution.

Demonstrated high-speed direct-writing of nanostructures.

Eliminated the need for expensive and toxic dyes in lithography.

Abstract

One-photon or two photon absorption by dye molecules in photopolymers enable direct 2D & 3D lithography of micro/nano structures with high spatial resolution and can be used effectively in fabricating artificially structured nanomaterials. However, the major bottleneck in unleashing the potential of this useful technique is the indispensable usage of dyes that are extremely expensive, highly toxic and usually insoluble in commercially available photopolymers. Here we report a simple, inexpensive and one-step technique for direct-writing of micro/nanostructures, with sub-wavelength resolution at extremely high speeds without using any one photon or two photon absorbing dye. We incorporated large amount (20 weight %) of inexpensive photoinitiator into the photopolymer and utilized its two-photon absorbing property for sub-wavelength patterning. Complex 2D and 3D patterns were fabricated with sub-micron resolution, in commercially available liquid photopolymer to show the impact/versatility of this technique.