Emerging Directions in Active and Multi-Layer Meta-Optics

Author: Gu, Yiran

Year: 2026

Degree: Dissertation (Ph.D.)

Advisor: Faraon, Andrei

Committee Members: Scherer, Axel; Vahala, Kerry J.; Marandi, Alireza; Faraon, Andrei

Option: Materials Science

Abstract

Meta-optics, composed of artificial nanostructures that enable precise control of light, have been widely studied for both fundamental science and technological applications. Compared to conventional bulky optical elements, they offer reduced size, weight, and power consumption, along with enhanced and multifunctional capabilities. As the field enters the transition from fundamental scientific exploration to scalable, real-world technologies, this thesis investigates emerging directions in meta-optics by integrating material and fabrication innovations, dispersion engineering, and inverse design to realize high-performance, scalable optical devices while overcoming key limitations of conventional metasurfaces. Active functionalities are demonstrated using silicon–organic slot metasurfaces, where enhanced light–matter interaction enables low-voltage electro-optic modulation, offering a pathway toward high-speed, CMOS-compatible free-space spatial light modulating devices. A central contribution lies in dispersion-engineered resonances, where concepts such as quasi-bound states in the continuum and band/zone folding are leveraged to achieve spectrally selective, and angle- or polarization-insensitive responses. In parallel, a novel fabrication platform for multilayer, high-index-contrast dielectric meta-optics in the visible regime is developed, enabling precise layer alignment and low-loss operation for volumetric photonic structures. Furthermore, a fabrication-robust inverse design framework is developed to realize compact and 3D photonic interconnects, addressing practical constraints in integrated systems. The advances are further connected to system-level applications through the demonstration of a dielectric metasurface-based coronagraph for space imaging. Together, this work establishes a unified framework for meta-optics that bridges fundamental physics, computational design, and advanced material and fabrication platforms, enabling scalable, multifunctional photonic systems for real-world applications.