Flat Optics With Metasurfaces and Their Applications

Abstract

At the heart of numerous developments in contemporary optics and photonics is the progressive understanding of the wave-matter interaction and our ability to manipulate or control it. This has in turn been largely driven by the discovery and use of metamaterials: synthetic, man-made materials whose constituent building blocks are engineered at a size scale similar to the characteristic wavelength of the system or phenomenon being studied. As such, these metamaterials often possess exotic properties that go beyond conventional, naturally occurring materials. However, their fabrication and large-scale reproduction have proven to be prohibitively challenging. Metasurfaces are two-dimensional analogs of metamaterials and are consequently much more compatible with standard industry fabrication processes, such as those commonly used in the electronics and semiconductor industries, while still expanding on many of the functions of conventional materials. This thesis presents how, in an optical context, single layer metasurfaces can perform at a level similar to their traditional refractive or diffractive counterparts in a variety of imaging and spectroscopic applications. More importantly, it details how metasurfaces can outperform these conventional optical elements by incorporating advanced dispersion engineering techniques in the design process, resulting in devices with a highly compact form-factor capable of performing sophisticated functions such as aberration control, broadband achromaticity and polarization management.