Multi-Photon 3D Lithography and Calcination for sub-100-nm Additive Manufacturing of Inorganics

Abstract

Development of 3D micro-/nanostructures leads to device miniaturization, enhanced function, and advanced integration opportunities in the fields of photonics, micro-fluidics, micro-mechanics, micro-electronics, and micro-optics. Multi-photon lithography (also widely known as two-photon polymerization) as a laser direct writing technique offers the flexibility to rapidly prototype 3D structure for additive manufacturing. Recent developments of this ultrafast laser technique together with the advances in material science allowed routine 3D printing of inorganic structures via a combination of mask-less photopolymerization and thermal post-treatment (pyrolysis and/or calcination). The present achievements are very promising for technical applications where highly resilient structures (made out of inert and durable materials) are required to withstand harsh environments, for high-intensity optics applications in open space industry. In this chapter, the physical and chemical principles for 3D nanostructuring of inorganics are covered via laser lithography of hybrid and composite materials with subsequent post-treatment. The most recent advances are overviewed, and the major achievements are highlighted including resilient sub-100-nm feature fabrication made of crystalline nanostructures, with a high refractive index and transparency. Advances and limitations within the context of the emerging trends and potential near-future applications are discussed in detail.