Additive Manufacturing of High-Refractive-Index, Nanoarchitected Titanium Dioxide for 3D Dielectric Photonic Crystals

Abstract

Additive manufacturing at small scales enables advances in micro-and nanoelectromechanical systems, micro-optics, and medical devices. Materials that lend themselves to AM at the nano-scale, especially for optical applications, are limited. State-of-the-art AM processes for high refractive index materials typically suffer from high porosity, poor repeatability, and require complex experimental procedures. We developed an AM process to fabricate complex 3D architectures out of fully dense titanium dioxide (TiO 2) with a refractive index of 2.3 and nano-sized critical dimensions. Transmission Electron Microscopy (TEM) analysis proves this material to be rutile phase of nanocrystalline TiO 2 , with an average grain size of 110 nm and <1% porosity. Proof-ofconcept woodpile architectures with 300-600 nm beam dimensions exhibit a full photonic bandgap centered at 1.8-2.9 μm, revealed by Fourier-transform Infrared Spectroscopy (FTIR) and supported by Plane Wave Expansion simulations. The developed AM process enables advances in 3D MEMS, micro-optics, and prototyping of 3D dielectric PhCs.

Laser Additive Manufacturing of Si/ZrO₂Tunable Crystalline Phase 3D Nanostructures

“…The latest research towards applications in photonics was focused on creating high refractive index materials, such as TiO 2 , again the spatial resolution within the range 300 -600 nm. 26 All in all, the results achieved in this study are ground braking in the context of repeatable additive manufacturing accuracy and crystalline phase tunability of 3D nanostructures.…”

High-resolution light field prints by nanoscale 3D printing

“…However, high refractive index materials also introduce stronger dispersion and reflective losses that diminish the optical performance of microlenses. Whilst more research is needed in nanoscale 3D printing of high refractive index materials 46 , the choice of a low refractive index material allowed the microlenses and pixels to be printed in a single process that greatly reduced the design constraints of our LFP. Another limitation is that the fabricated structures of the LFP are fragile and can be easily wiped off by hand.…”

Three‐dimensional chemical reactors: in situ materials synthesis to advance vat photopolymerization

“…130 The absence of light-scattering particles in these inorganic-organic photoresins allows them to be used with TPL to attain features with sub-micron resolution. 131,132 Gailevičius et al described the use of a zirconium-and siliconcontaining inorganic-organic photoresin with TPL to fabricate silica-zirconia 3D structures with 85 nm features. 133 The main drawback with this approach is that it is often limited to siliconbased ceramics, 134,135 binary transition metal oxides, 136 and oxide glasses.…”