Fabrication of Waveguides and Other Optical Elements by Multiphoton Lithography

Summary

Lithography is a common technique for the fabrication of photonic circuits and circuit elements. In complementary metal oxide semiconductor (CMOS) fabrication, negative photoresists are transient. By comparison, photo‐cured polymers in photonic integrated circuits (ICs) are meant to last for many years and to retain the optical and mechanical properties required for their application. Acrylate monomers are the principal components of resins for traditional stereolithography (SLA) and, unsurprisingly, are widely used for multiphoton lithography (MPL) as well. Multiphoton absorption (MPA) can induce changes in the optical properties of a material by numerous mechanisms. Composites, in particular nanocomposites, are intensively studied for optical applications because of the great breadth in material properties. Organic modified ceramics (ORMOCER) are a popular class of nanocomposites, known both for their excellent material properties and for ease of processing. ORMOCER photosensitive resins consist of sol‐gel‐erived oligomers containing organic and inorganic groups, purely organic monomers, and other additives including a photoinitiator.