X-photon 3D lithography by fs-oscillators: wavelength-independent and photoinitiator-free

Abstract

Laser direct writing employing multi-photon 3D polymerisation is a scientific and industrial tool used in various fields such as micro-optics, medicine, metamaterials, programmable materials, etc., due to the fusion of high-throughput and fine features down to hundreds of nm. Some limitations of technology applicability emerge from photo-resin properties, however any material modifications can strongly affect its printability, as photoexcitation conditions alter as well. Here we present wavelength-independent 3D polymerisation using low peak power laser oscillators. High pulse repetition rate and fast laser direct writing was employed for advancing additive manufacturing out of the SZ2080TM photo-resist without any photo-initiator. Wavelengths of 517 nm, 780 nm, and 1035 nm are shown to be suitable for producing 300 nm polymerized features even at high – up to 100 mm/s – writing speeds. Variation of organic-inorganic ratio in hybrid material results in shift and decrease of the dynamic fabrication window, yet not prohibiting the photo-structuring. Controlled energy deposition per focal volume is achieved due to localized heating enabling efficient 3D printing. Such spatio-selective photo-chemical cross-linking widens optical manufacturing capacity of non-photo-sensitive materials.

YAG:Ln for laser 3D lithography: precursor synthesis and study

“…Objective lens used for 3D woodpile fabrication was of 50times magnification and 0,75 numerical aperture(NA). Intensity was estimated using the same nomenclature elaborated elsewhere by D. Ladika et al 17 LDW was carried out in the green wavelengths with a peak at 517 nm. LDW 3D printing settings used in this work were very similar to those described in a work done by A. Butkus et al [ 18 ].…”