Processes of Laser Direct Writing 3D Nanolithography

Abstract

Direct laser writing three-dimensional nano-lithography is an established technique for manufacturing functional 3D micro-and nano-objects via non-linear absorption induced polymerization process. In this Chapter an underlying physical mechanisms taking place during nano-confined polymerization reaction, induced by tightly focused ultra-short laser pulses, are reviewed and discussed. The special attention is paid on the effects that directly impact structuring resolution and minimum achievable feature size. Analysis of possible photo-initiation mechanisms as contributing multi-photon absorption and avalanche ionization in pre-polymers under diverse exposure conditions (wavelength, pulse duration) is presented. Feasible structuring of pure (non-photosensitized) and functional nanoparticles doped polymer precursors is justified and benefits of such materials/structures for microoptics, photonics and cell scaffolds are highlighted. The influence of temperature effects (induced by writing process itself or determined by ambient conditions) on polymerization process, observed in different pre-polymers under diverse exposure regimes is outlined. The further adjustment of the structuring resolution is possible via precise control of light polarization and diffusion assisted radical quenching. The work is concluded with a brief outlook on future challenges and perspectives related to refinement of 3D ultra-fast laser lithography fabrication process in the means of application of diverse post-processing methods and research into novel photo-curable materials including inorganic ones.

Two-Photon Polymerization of 2.5D and 3D Microstructures Fostering a Ramified Resting Phenotype in Primary Microglia

“…Fabrication of micro- and nanotopographies as well as 3D biomimetic scaffolds ( Fan et al, 2019 ) for in vitro studies can be performed via multiple techniques such as emulsion templating ( Riesco et al, 2019 ), electrospinning ( Pires et al, 2015 ; Wissing et al, 2019 ; Venugopal et al, 2021 ), stereolithography ( Gauvin et al, 2012 ), and two-photon polymerization (2PP) ( Lemma et al, 2019 ; Varapnickas and Malinauskas, 2020 ) to name a few. While each of these fabrication methods has its own advantages, 2PP especially stands out due to its extremely high resolution (∼50–200 nm) ( Malinauskas et al, 2010 ; Emons et al, 2012 ), ability to fabricate complex 3D geometries using computer-aided design (CAD) models, and high reproducibility.…”

Two‐Photon Polymerization Lithography for Optics and Photonics: Fundamentals, Materials, Technologies, and Applications

“…Their products and equipment have been widely applied to realize complex 3D structures in a variety of fields, for example, optics and photonics, biology, mechanics, acoustics, electronics, materials, etc. [ 63–75 ]…”

“…Their products and equipment have been widely applied to realize complex 3D structures in a variety of fields, for example, optics and photonics, biology, mechanics, acoustics, electronics, materials, etc. [63][64][65][66][67][68][69][70][71][72][73][74][75] As a direct laser writing (DLW) technology, TPL is well positioned for optical and photonic applications with fabrication capabilities of arbitrary 3D shapes. The polymerized structures are generally transparent in the visible band, with surface roughness < 10 nm, thus this technology has been intensively investigated and used to manipulate light since its inception.…”