Acrylate‐Based Photopolymer for Two‐Photon Microfabrication and Photonic Applications

Abstract

This paper provides a photopolymerizing material suitable for stereolithography of complex submicrometer‐sized three‐dimensional (3D) structural elements to a broad scientific public. Here, we present the formulation of a polymer (LN1 resin) that allows further research in the field of nanofabrication and ‐technology as it surpasses current material limitations. The polymer consists of multifunctional acrylate oligomers as binder, polyfunctional monomers, and a photoinitiator (PI). The chemistry to form 3D structures is based on photopolymerization of the acrylate system initiated by free‐radical species that are triggered by two‐photon absorption of a PI. Important parameters of photocuring, such as the effects of PI concentration, temperature, and light intensity, were studied using photocalorimetry. The thermal stability of the material was tested using thermal gravimetric analysis, providing key information for electronic and photonic applications. Photonic‐crystal structures generated from this resin exhibiting photonic stop gaps in near‐infrared‐ and telecommunication‐wavelength regions are presented.

Laser‐Directed Assembly of Aligned Carbon Nanotubes in Three Dimensions for Multifunctional Device Fabrication

“…[ 28 ] The reasons for choosing pentaerythritol tetrakis (PETMP) and di-trimethylolpropane tetraacrylate (Di-TMPTTA) are their miscibility and branched structures, which favor the formation of highly cross-linked networks. The photoinitiator of 2-Benzyl-2-(dimethylamino)-4′-morpholinobutyrophenone (BDMP) was used due to its high initiation effi ciency and large absorbance in the 300-400 nm wavelength range, [ 29 ] which is suitable for TPP lithography. The as-prepared resins showed excellent dispersion of MWNTs through the composite resins and had a high stability which could last for one week under ambient conditions without Using TPP lithography, a fs laser beam (center wavelength of 780 nm, pulse width of 100 fs, and repetition rate of 80 MHz) was tightly focused into the MTA resin to make 3D scans according to geometric user designs, resulting in solidifi ed 3D micro/nanostructures with MWNTs simultaneously incorporated inside the polymer.…”

Introducing Defects in 3D Photonic Crystals: State of the Art

“…MPP was first developed by Strickler and Webb, [62] and has now been used to create a range of high-resolution 3D free-form structures, including microchannels, [63][64][65] cantilevers, [66][67][68] microgears, [69,70] sub-micrometer oscillators, [71] hydrophobic atomic force microscopy tips, [72] and PhCs. [59,67,[73][74][75][76][77][78][79][80][81] Briefly, MPP utilizes the nonlinear nature of the multiphoton excitation process to only excite dye molecules in a very small volume around the focal point, with dimensions on the order of the resolution limit. These excited dye molecules locally initiate a polymerization.…”

Dual wavelength multiphoton absorption

“…[7] ORMOCER contains a highly cross-linkable organic network and inorganic components leading to high optical quality and mechanical and thermal stability. ORMOCER has been extensively studied as a material for two-photon polymerization, and several devices have been made with them, the most notable being a photonic crystal built up from individual.…”