Introduction to Metalens Optics

Until recently, the field of optics was dominated by refractive and diffractive lenses. In the early 2010s, a new type of lens, the plasmonic metalens appeared in the research arena. But it was in the late 2010s that an optics revolution began with the dielectric metalens. Since then, metalenses have developed powerful capabilities beyond traditional lenses with flat surfaces, reduced thickness, and promising imaging capabilities. A metalens is an ultra-flat lens made by a special metasurface, which radially arranges many nano-optical elements over the surface, to transform incoming wavefronts for focusing light. Metalenses are 2D lenses with focusing and imaging functions, and with promising applications in miniature optical systems, such as mobile devices. The study of metalenses is part of the field of meta-optics or flat optics. Today, metasurfaces and metalenses are one of the most fascinating advances in modern optics and are continuously evolving.

This book provides an overview of the basic optics of the metalens, providing an introduction for students, scientists and engineers. The scope of this book is to introduce the optical fundamentals and basic optical design methods of a metalens, where light propagation can be modelled by simple, and yet useful basic optics (e.g., the refraction law of metasurfaces, the wave front propagation, the metasurface phase profile, meta-atoms, etc.). The book provides the historical background about metasurfaces and the metalens, reviews the basics of metalens optics, the main metalens simulation tools, the design and analysis of meta-atoms, and the optical design of metalens. This basic introduction to metalens optics may provide a practical starting point for the study of the next generation of flat lenses based in nanotechnology.