Design, Realization, and Applications of 3D Multifunctional Nanophotonics

Author: Roberts, Gregory David

Year: 2024

Degree: Dissertation (Ph.D.)

Advisor: Faraon, Andrei

Committee Members: Bruno, Oscar P.; Vahala, Kerry J.; Marandi, Alireza; Faraon, Andrei

Option: Applied Physics

DOI: 10.7907/1r1w-0234

Abstract

Metaoptics leverages electromagnetic phenomena and the advanced abilities of modern nanofabrication to replicate traditional optical devices in a fraction of the thickness and to realize novel, compact, multifunctional devices with no known bulk equivalent. Motivated by the expanding role of optics in modern technologies, this field has seen a rise in design techniques for realizing increasingly powerful photonic structures. Three-dimensional (3D) devices, with refractive index distributions patterned at subwavelength scales, represent an enormous design space capable of achieving highly efficient, free space, multifunctional structures. By utilizing a gradient-based, iterative optimization algorithm, a technique for nanophotonic inverse design, we demonstrate scattering structures with unique responses to all the fundamental properties of light. The algorithm is constrained such that resulting devices can be made with realistic multilayer fabrication processes. We present dielectric structures that can be placed directly on top of image sensor arrays and sort light to different pixels based on its wavelength, polarization, and angular momentum, thus enabling efficient and exotic camera technologies. The following work contains fabrication and measurement of 3D devices in the mid-infrared, practical evaluations of devices for visible light imaging applications, and visualizations of underlying structure of photonic design optimization problems.

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