자료유형  

 학위논문

Control Number  

0016931970

International Standard Book Number  

9798379653750

Dewey Decimal Classification Number  

770

Main Entry-Personal Name  

Klopfer, Elissa Ann.

Publication, Distribution, etc. (Imprint  

[S.l.] : Stanford University., 2023

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Physical Description  

1 online resource(126 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 84-12, Section: B.

General Note  

Advisor: Brongersma, Mark L.;Lindenberg, Aaron Michael;Dionne, Jennifer.

Dissertation Note  

Thesis (Ph.D.)--Stanford University, 2023.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Wavefront shaping and control is essential for advancing optical technologies spanning communication, computation, and sensing. Metasurfaces promise to miniaturize future optical components, like beam steerers and lenses, for lightweight, compact, and on-chip platforms. These devices achieve this by shaping light with subwavelength nanostructures that precisely control the wave's amplitude, polarization, and phase. However, most current metasurface designs are static, unable to flexibly tune their responses to environmental or operational cues once fabricated.This thesis presents the design, fabrication, and characterization of dynamic metasurfaces that eciently modulate their behavior based on the integration of high quality factor (high-Q) resonances. Silicon nanobars constitute the basis for each metasurface's nanoantenna elements, and simultaneously support high-Q modes along their length and spatial control across the other metasurface dimension. High-Q resonances have two primary features that augment metasurface tuning mechanisms. First, high-Q resonances are characterized by very sharp spectral features that are extremely sensitive to refractive index variation, allowing even small perturbations to strongly vary the resulting optical response. Second, high-Q resonances are accompanied by strongly enhanced near fields, which can improve modulation mechanisms that rely on electromagnetic near-fields, such as nonlinearities.Through demonstrating a variety of devices both theoretically and experimentally this thesis will clearly lay out high-Q wavefront shaping metasurfaces as a promising route to achieving active devices utilizing many possible modulation mechanisms to realize a variety of transfer functions. First, we demonstrate tunable high-Q phase gradient lensing, with ecient nonlinear modulation. The integration of the resonance enhances the otherwise negligible nonlinear Keff effect in silicon, and controlling the spectral position of the resonance enables high-fidelity modulation of the overall focal characteristics. Furthermore, this device realizes a power limiting-like behavior that has the potential to protect the device when operating at high powers. Then, we investigate high-Q lensing via a zone plate architecture to experimentally demonstrate high-Q tuning for the first time, through the thermo-optic effect. By carefully designing the broad background optical characteristics as well as the high-Q resonance, these lenses operate for only the narrow bandwidth of the resonance. This device demonstrates the ability to tune its operating wavelength and acts as a switchable device.Finally, we design and numerically demonstrate a fully reconfigurable beam splitting and beam steering through individual electro-optic control. The inclusion of lithium niobate and direct control of each resonance in the device opens up full operational control through voltage biasing. In full, this thesis will show how high-Q resonant wavefront shaping metasurfaces realize ecient active devices through enhanced modulation mechanisms and novel design schemes.

Subject Added Entry-Topical Term  

Cameras.

Subject Added Entry-Topical Term  

Electromagnetism.

Subject Added Entry-Topical Term  

Optics.

Subject Added Entry-Topical Term  

Geometry.

Subject Added Entry-Topical Term  

Radiation.

Subject Added Entry-Topical Term  

Pandemics.

Subject Added Entry-Topical Term  

Electromagnetics.

Subject Added Entry-Topical Term  

Physics.

Added Entry-Corporate Name  

Stanford University.

Host Item Entry  

Dissertations Abstracts International. 84-12B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:640523