Date Approved

1-10-2023

Embargo Period

1-11-2023

Document Type

Thesis

Degree Name

M.S. Mechanical Engineering

Department

Mechanical Engineering

College

Henry M. Rowan College of Engineering

Advisor

Chen Shen, Ph.D.

Committee Member 1

Ratneshwar Jha, Ph.D.

Committee Member 2

Ben Wu, Ph.D.

Keywords

cavity resonators, dielectric scatters, embedded eigenstates, bound states in the continuum

Subject(s)

Photonics

Disciplines

Electrical and Computer Engineering | Mechanical Engineering | Physics

Abstract

Bound states in the continuum (BICs) are waves that remain in the continuous spectrum of radiating waves that carry energy, however, still localized within the spectrum. BICs, also embedded eigenmodes, exhibit high quality factors that have been observed in optical and acoustic waveguides, photonic structures, and other material systems. Presently, there are limited means to select these BICs in terms of the quality factor and their excitation. In this work, we show that a different type of BIC, Quasi-BICs (Q-BICs), in open resonators can have their quality attuned by introducing embedded scatters. Using microwave cavities and dielectric scatters as an example, we show that by tuning the geometry of the structure and the specific locations of the dielectric scatters Q-BICs can be selectively chosen to exhibit enhancements to their quality. The coupled mode theory (CMT) and numerical simulations are employed to inspect the altering of dielectrics, structure parameters, and tuning of the quality factor for the Q-BICs chosen. These results may be beneficial to the application of enhanced optical lasers, sensors, open structures that need contained radiation and control over selectivity.

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