A Field Guide to Azopolymeric Optical Fourier Surfaces and Augmented Reality

Optical Fourier surfaces (OFSs) are used for various applications, from diffractive optics to augmented reality (AR). However, the current methods of fabricating OFSs primarily rely on lithographic photochemical reactions and etching. These methods are likely to fabricate digitalized binary reliefs, which cannot match the ideal surface profile of OFSs. Such a profile is the sum of sinusoidal surfaces with various spatial frequencies. As an exception, scanning probe lithography (SPL) is found to be compatible with OFSs. However, the accessible pattern area of the OFSs created via SPL is relatively small owing to the serial feature of the fabrication, which in turn results in an undesired and complicated Fourier spectrum. In this article, the holographic inscription is redesigned for the low-cost, large-area, and rapid prototyping of customized OFSs. To this end, an integrative pipeline is established across numerical design, material optimization, and the pragmatic considerations of optical processing. Then, a soft molding strategy is suggested for optically transparent and flexible OFSs and its use for easy-to-craft AR devices. Overall, this intuitive framework not only expands the scope of Fourier optics but also acts as a field guide to azopolymeric OFSs and AR technology for experts and newcomers alike.