Multiphoton Lithography

Jurgen Stampfl studied Applied Physics at the University of Technology in Graz (Austria) and received his PhD in Materials Science from the University of Leoben (Austria) in 1996. From 1997 to 2000, he worked as a research associate at the Rapid Prototyping Lab at Stanford University (USA). In 2001, he joined the Institute of Materials Science and Technology at the Vienna University of Technology (Austria), where he was appointed associate professor for Materials Science in 2005. He is head of the working group Functional Non-Metals and since 2012 (together with Robert Liska) head of the Christian Doppler Laboratory for photopolymers in digital and restorative dentistry. His expertise lies in the field of additive manufacturing technologies and the development and characterization of advanced materials. Robert Liska received his PhD from the Vienna University of Technology (Austria) in 1998. In 2006, he completed his habilitation with a work on the topic of macromolecular chemistry. He is leader of the research group Photopolymerization at the Institute of Applied Synthetic Chemistry at the Vienna University of Technology. In 2012, he became head of the Christian Doppler Laboratory for photopolymers in digital and restorative dentistry and since 2016 he is full professor for organic technology. He is interested in the research topics photoinitiation, photopolymerization, additive manufacturing, and biomedical polymers. Liska is co-author of eight book chapters and of more than 100 peer-reviewed journal articles. Dr. Aleksandr Ovsianikov is currently an Assistant Professor at Vienna University of Technology (TU Wien, Austria). His research is dealing with the use of additive manufacturing technologies for tissue engineering and regeneration. Dr. Ovsianikov has background in laser physics and material processing with femtosecond lasers. After undergraduate studies at the Vilnius University (Lithuania) he completed his PhD at the Nanotechnology Department of the Laser Zentrum Hannover, and received his degree from the University of Hannover (Germany) in 2008. A particular focus of the current research of Dr. Ovsianikov is the development of multiphoton processing technologies for engineering biomimetic 3D cell culture matrices. In 2012 he was awarded a prestigious Starting Grant from the European Research Council (ERC) for a project aimed at this topic. Since 2004 Dr. Ovsianikov has contributed to over 60 publications in peer-reviewed journals and 5 book chapters.

• List of Contributors XIForeword XVIIIntroduction XIXPart I Principles of Multiphoton Absorption 11 Rapid Laser Optical Printing in 3D at a Nanoscale 3Albertas Žukauskas, Mangirdas Malinauskas, Gediminas Seniutinas, and Saulius Juodkazis1.1 Introduction 31.2 3D (Nano)polymerization: Linear Properties 41.2.1 Photocure andThermal Cure of Photoresists 51.2.2 Tight Light Focusing 61.2.3 Optical Properties at High Excitation: From Solid to Plasma 81.2.4 Heat Accumulation 101.3 3D (Nano)polymerization: Nonlinear Properties 131.3.1 Strongest Optical Nonlinearities 131.3.2 Avalanche Versus Multiphoton Excitation 151.4 Discussion 171.5 Conclusions and Outlook 18Acknowledgments 19References 192 Characterization of 2PA Chromophores 25EricW. Van Stryland and David J. Hagan2.1 Introduction 252.2 Description of Nonlinear Absorption and Refraction Processes 262.2.1 Two-Photon Absorption and Bound-Electronic Nonlinear Refraction 262.2.2 Excited-State Absorption and Refraction 282.3 Methods for Measurements of NLA and NLR 312.3.1 Direct Methods 312.3.1.1 Nonlinear Transmission 312.3.1.2 Z-Scan 322.3.1.3 Determining Nonlinear Response from Pulse-width Dependence of Z-Scans 392.3.1.4 White-Light-Continuum Z-Scan (WLC Z-Scan) 412.3.1.5 Other Variants of the Z-Scan Method 432.3.2 Indirect Methods 452.3.2.1 Excitation–Probe Methods 452.3.2.2 White-Light-Continuum (WLC) Excite–Probe Spectroscopy 482.3.2.3 Degenerate Four-Wave Mixing (DFWM) 512.3.2.4 Two-Photon-Absorption-Induced Fluorescence Spectroscopy 532.3.2.5 Fluorescence Anisotropy 552.4 Examples of Use of Multiple Techniques 552.4.1 Squaraine Dye 562.4.2 Tetraone Dye 572.5 Other Methods 592.6 Conclusion 60Acknowledgments 60References 603 Modeling of Polymerization Processes 65Alexander Pikulin and Nikita Bityurin3.1 Introduction 653.2 Basic Laser Polymerization Chemistry and Kinetic Equations 663.3 Phenomenological PolymerizationThreshold and Spatial Resolution 693.4 Effect of Fluctuations on the Minimum Feature Size 753.5 Diffusion of Molecules 833.5.1 Diffusion of the Growing Chains 843.5.2 Diffusion of Inhibitor: Diffusion-Assisted Direct LaserWriting 863.6 Conclusion 90Acknowledgements 91References 91Part II Equipment and Techniques 954 Light Sources and Systems for Multiphoton Lithography 97Ulf Hinze and Boris Chichkov4.1 Laser Light Sources 974.2 Ultrashort-Pulse Lasers 984.3 Laboratory Systems and Processing Strategy 1004.4 Further Processing Considerations 105References 1085 STED-Inspired Approaches to Resolution Enhancement 111John T. Fourkas5.1 Introduction 1115.2 Stimulated Emission Depletion Fluorescence Microscopy 1135.3 Stimulated Emission Depletion in Multiphoton Lithography 1175.4 Photoinhibition 1225.5 Inhibition Based on Photoinduced Electron Transfer 1235.6 Absorbance Modulation Lithography 1265.7 Challenges for Two-Color, Two-Photon Lithography 1275.8 Conclusions 128Acknowledgments 128References 128Part III Materials 1336 Photoinitiators for Multiphoton Absorption Lithography 135Mei-Ling Zheng and Xuan-Ming Duan6.1 Introduction for Photoinitiators for Multiphoton Absorption Lithography 1356.1.1 Multiphoton Absorption Lithography 1356.1.2 Photoinitiators for Multiphoton Absorption Lithography 1356.1.2.1 History of the Design of Two-Photon Initiators 1356.1.2.2 Property of Two-Photon Initiators 1366.1.3 Characterization of Two-Photon Initiators 1376.1.4 Molecular Design for Photoinitiators 1406.2 Centrosymmetric Photoinitiators 1416.3 Noncentrosymmetric Photoinitiators 1536.4 Application of Photoinitiators in Multiphoton Absorption Lithography 1566.5 Conclusion 162Acknowledgment 163References 1637 Hybrid Materials for Multiphoton Polymerization 167Alexandros Selimis and Maria Farsari7.1 Introduction 1677.2 Sol–Gel Preparation 1687.3 Silicate Hybrid Materials 1697.4 Composite Hybrid Materials 1717.5 Surface and Bulk Functionalization 1737.6 Replication 1757.7 Conclusions 176References 1768 Photopolymers for Multiphoton Lithography in Biomaterials and Hydrogels 183Mark W. Tibbitt, Jared A. Shadish, and Cole A. DeForest8.1 Introduction 1838.2 Multiphoton Lithography (MPL) for Photopolymerization 1868.3 MPL Equipment for Biomaterial Fabrication 1888.4 Chemistry for MPL Photopolymerizations 1898.4.1 Photopolymerization 1898.4.2 Photoinitiator Selection 1918.4.3 Photopolymer Chemistries 1938.4.3.1 Macromer Chemistries 1938.4.3.2 Photochemical Polymerization and Degradation 1948.5 Biomaterial Fabrication 2028.6 Biomaterial Modulation 2038.7 Biological Design Constraints 2068.8 Biologic Questions 2088.9 Outlook 209References 2109 Multiphoton Processing of Composite Materials and Functionalization of 3D Structures 221Casey M. Schwarz, Christopher N. Grabill, Jennefir L. Digaum, Henry E.Williams, and Stephen M. Kuebler9.1 Overview 2219.2 Polymer–Organic Composites 2259.2.1 Fluorescent-Dye-Doped Organic Microstructures 2259.2.2 Organic Composites for Lasing Microstructures 2279.2.3 Organic Composites for Electrically Conductive Microstructures 2279.2.4 Other Optically Active Microstructures 2299.3 Multiphoton Processing of Oxide-Based Materials 2309.3.1 Titanium Dioxide 2319.3.2 Zinc Oxide 2319.3.3 Zirconium Dioxide 2329.3.4 Iron Oxide 2329.3.5 Tin Dioxide 2339.3.6 Germanium Dioxide 2349.3.7 Silicon Dioxide 2349.4 Multiphoton Processing of Metallic Composites and Materials 2359.4.1 Thermal Evaporation 2369.4.2 e-Beam Evaporation 2369.4.3 Magnetron Sputtering 2369.4.4 Chemical Vapor Deposition 2379.4.5 Functionalization by Attachment of Nanoparticles 2389.4.6 Electroless Metallization from Solution 2399.4.7 Multiphoton Lithography of Nanoparticles Supported in a Polymer Matrix 2429.4.8 DirectWriting of Continuous-Metal Microstructures 2449.4.9 Metal Backfilling by Electroplating 2459.5 Multiphoton Processing of Semiconductor Composites and Materials 2469.5.1 Structures Functionalized with Nanoparticles 2469.5.2 Structures Functionalized using NP–Polymer Composites 2469.5.3 Structures Functionalized by In Situ NP Formation 2479.5.4 Structures Functionalized by NP Coating 2489.5.5 Structures Functionalized by Silicon Inversion 2509.5.6 Functional Structures Fabricated in Bulk Chalcogenide Glasses 2529.5.7 Structures Fabricated in ChG Film 2529.5.8 Structures Fabricated in ChG–NP Composites 2549.6 Conclusion 254Acknowledgments 255References 255Part IV Applications 26510 Fabrication ofWaveguides and Other Optical Elements by Multiphoton Lithography 267Samuel Clark Ligon, Josef Kumpfmüller, Niklas Pucher, Jürgen Stampfl, and Robert Liska10.1 Introduction 26710.2 Acrylate Monomers for Multiphoton Lithography 26810.3 Thiol–Ene Resins 27710.4 Sol–Gel-Derived Resins 28010.5 Cationic Polymerization and Stereolithography 28410.6 Materials Based on Multiphoton Photochromism 28710.7 Conclusions 292Acknowledgments 292References 29211 Fabricating Nano and Microstructures Made by Narrow Bandgap Semiconductors and Metals using Multiphoton Lithography 297Min Gu, Zongsong Gan, and Yaoyu Cao11.1 Introduction 29711.2 Fabrication of 3D Structures Made by PbSe with Multiphoton Lithography 29811.2.1 Challenges of Multiphoton Lithography with Top-Down Approach for Narrow Electronic Bandgap Semiconductors 29811.2.2 Photoresin Development 29911.2.3 Two-Photon Lithography of PbSe Structures 30211.2.4 Confirmation of PbSe Formation 30311.3 Fabrication of Silver Structures with Multiphoton Lithography 30411.3.1 Principle of Resolution Improvement by Increasing Photosensitivity in Photoreduction 30511.3.2 Photosensitivity Enhancement by Tuning LaserWavelength 30511.3.3 Dot Size Model Based on Photosensitivity 30811.3.4 Further Increase the Photosensitivity with an Electron Donor 31011.4 Conclusions 310Acknowledgments 312References 31212 Microfluidic Devices Produced by Two-Photon-Induced Polymerization 315Shoji Maruo12.1 Introduction 31512.2 Fabrication of Movable Micromachines 31612.3 Optically Driven Micromachines 32012.4 Microfluidic Devices Driven by a Scanning Laser Beam 32512.5 Microfluidic Devices Driven by a Focused Laser Beam 32712.6 Microfluidic Devices Driven by an Optical Vortex 33012.7 Future Prospects 331References 33213 Nanoreplication Printing and Nanosurface Processing 335Christopher N. LaFratta13.1 Introduction: Limitations of Multiphoton Lithography 33513.2 Micro-transfer Molding (μTM) 33613.3 μTM of Complex Geometries 33813.4 Nano-replication of Other Materials 33913.5 Nanosurface Metallization Processing 34213.6 Nanosurface Structuring via Ablation 34413.7 Conclusion and Future Directions 349References 351Part V Biological Applications 35314 Three-Dimensional Microstructures for Biological Applications 355Adriano J. G. Otuka, Vinicius Tribuzi, Daniel S. Correa, and Cleber R. Mendonça14.1 Introduction 35514.2 3D Structures for Cells Studies 35714.3 Biocompatible Materials 36314.4 Scaffolds for Bacterial Investigation 36814.5 Microstructures for Drug Delivery 37114.6 Final Remarks 374References 374Index 377