Tutorial SF14—The Foundations of 3D Laser Nanoprinting

This tutorial session covers the fundaments of 3D laser nanoprinting technology (aka direct laser writing), based on the multi-photons polymerization process. Selected lectures cover the different aspects of the technology, including physical principles, chemistry of the materials and state-of-the-art applications.

Introduction to 3D Laser Nanoprinting
Martin Wegener, Karlsruhe Institute of Technology

In this lecture, I will give an introduction to the principles of 3D laser printing on the nano- and micrometer scale. The nonlinearity that is necessarily required to spatially localize the excitation in all three dimensions can be provided by optics (i.e., two- or multi-photon absorption or two-step absorption), by chemistry (i.e., the diffusion-reaction kinetics) or by combinations thereof. Achievable voxel sizes and spatial resolutions will be discussed. In-situ diagnostics can help to understand the underlying mechanisms and timescales. Stimulated emission depletion (STED) inspired approaches can beat the diffraction limit, precisely, the multi-photon Sparrow criterion. State-of-the-art of 3D laser nanoprinting is systematically compared with other 3D additive manufacturing approaches in terms of printing rate and spatial resolution. Selected examples are given.

The Chemistry of 3D Laser Printing
Colm Delaney, Trinity College Dublin

This lecture will cover all areas of development of polymeric materials for 3D laser printing. It will introduce suitable chemistries for two-photon (or multi-photon) photoresist development. The focus will not only be placed on conventional acrylate chemistries, but viable alternatives for the generation of polymeric structures via 2PP will also be discussed in detail. Emphasis will also be placed on the inclusion of solvents for photoresist creation, their influence on the polymerization process and the resulting structures. Lastly, a discussion of suitable photoinitiator systems will be carried out, covering classic photoinitiators for the 2PA process and recent developments in water-soluble and biocompatible photoinitiators. These will all be covered in the context of recent advances in the field and state-of-the-art in academic and industrial research.

Functional Materials for 3D Laser Printing
Marco Carlotti, Italian Institute of Tehcnology

This lecture will cover the fundamentals of two-photon lithographic methodologies based on inherently-functional photoresists with particular focus on the application to functional micro-devices.

It will introduce the possibilities offered by both functional homogeneous formulations and nanocomposites, discussing their advantages and limitations relative to different applications. Particular attention will also be given to the characterization of the properties and performances of the final microstructures and devices.

During the tutorial, state-of-the-art technologies will be presented and we will discuss how they relate to similar systems commonly employed in other additive manufacturing platforms. Finally, we will explore the possibilities offered by the combination of two-photon approaches with standard lithographic techniques for the fabrication of functional MEMS through 3D microprinting.