Chapter 12.1 - 3D Micro-Optics Via Ultrafast Laser Writing: Miniaturization, Integration, and Multifunctionalities

Abstract

Advances of the growing field of micro-optical elements and components created via direct laser writing (DLW) are overviewed. The basic principles and the most recent developments in three-dimensional (3D) DLW in polymers enable creation of miniaturized and integrated optical devices. The employed technique based on femtosecond laser pulses provides efficient and reliable structuring with up to ∼100 nm feature definition as well as less than 10 nm surface roughness required for optical/photonic applications. Research into the structuring by ultrashort laser pulses has seen immense growth over the past decade due to its unique material processing features involving linear and nonlinear photophysical and photochemical mechanisms. This enables nanostructuring of pure organic, hybrid organic–inorganic, as well as hydrogel or elastomer materials via avalanche-induced cross-linking, thus without the usage of any photosensitizers. This approach empowers manufacturing of the low optical losses and high damage threshold, as well as biocompatible elements. Examples of various micro-optical elements are provided with focus on refractive index measurement and engineering for a particular optical function along with unique performance of the miniature devices.