Date of Award

Winter 12-15-2021

Document Type

Thesis

Degree Name

Master of Science in Optical Engineering

Department

Department of Physics and Optical Engineering

First Advisor

Alisafaee, Hossein

Second Advisor

Granieri, Sergio

Third Advisor

Kim, Dong Hwan

Abstract

The development of a non-scanning laser-based imaging lidar system based on a diffractive optical element with potential applications in advanced driver assistance systems, autonomous vehicles, drone navigation, and mobile devices is reported. The proposed lidar utilizes image processing with homography. The emphasis in the design approach has been on compactness and cost of the final system for it to be deployable both as standalone or complementary to existing lidar sensors, enabling fusion sensing in the applications. This work describes the basic elements of the proposed lidar system. It presents the potential ranging mechanisms, along with their experimental results demonstrating the performance of our prototype in real-time. Also, the nano-illumination using metasurface is investigated to improve resolution and enable customized diffraction patterns for various applications. The phase masks of two target patterns of i) Gradient grid pattern for lidar application, and ii) Economic Commission for Europe (ECE) low beam pattern for lighting were calculated by iterative Fourier transform algorithm with MATLAB. In order to decide the metacell structure shape of the metasurface based on the calculated phase maps, the metacell simulations were progressed. The metacell simulations with a thickness of 100, 200, and 600 nm and the shape of a pillar, hole, ring, and core-shell with PMMA, TiO2, and both were conducted to find the phase modulation. Subsequently, the optimal conditions of e-beam lithography to fabricate the metacell structure with a high aspect ratio were found by sample pattern fabrication in various conditions and its result analysis. Herein, each step for the realization of the metasurface design is described, and this work suggests the feasibility of the new potential area of nano-illumination in the metasurface field.

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