Silica Nanoparticle-Based Photoresin for THz High-Resolution 3-D Microfabrication by Two-Photon Polymerization

Abstract

Two-photon polymerization is a promising fabrication technique for complex three-dimensional (3D) structures operating at TeraHertz (THz) given its sub- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m resolution with hundreds of mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> print volume capability. However, standard photoresins exhibit unsuitably high THz absorption and have poor mechanical, chemical, and thermal stability. To address the latter three issues, a new photoresin (commercially known as GP-Silica) based on silica nanoparticles dispersed in a photocurable binder matrix has been recently developed. To assess its suitability for THz devices, we report the THz dielectric properties of GP-Silica and compare them with standard 3D printable materials. We find that GP-Silica outperforms the other photoresins by almost 5 times in terms of absorption, which finally unlocks additive manufacturing for THz applications.