Band engineering in structured photonic systems Shupeng Xu

Format:

Book

Thesis/Dissertation

Author/Creator:

Xu, Shupeng, author.

Contributor:

University of Pennsylvania. Materials Science and Engineering., degree granting institution.

Language:

English

Subjects (All):

Condensed matter physics.

Optics.

Materials science.

Nanotechnology.

0611.

0752.

0794.

0652.

Local Subjects:

Condensed matter physics.

Optics.

Materials science.

Nanotechnology.

0611.

0752.

0794.

0652.

Genre:

Academic theses

Physical Description:

1 online resource (156 pages)

Contained In:

Dissertations Abstracts International 87-12B

Place of Publication:

Ann Arbor : ProQuest Dissertations and Theses, 2026

Language Note:

English

Summary:

This thesis presents studies of band engineering in structured photonic systems, in which geometry, symmetry, and periodic patterning are used as design principles to access topological phases, flat bands, and nonlinear optical responses that are unavailable in unstructured settings. Both the dispersion and the geometric structure of Bloch states provides the unifying theoretical language connecting the works presented here. We begin by revisiting the Wu-Hu model of topological photonic crystals, establishing a careful algebraic classification of its topological properties using topological quantum chemistry and clarifying topological nature of its edge states. We then construct a photonic flatband with fragile topology in a coupled resonator system, demonstrating the Wannier obstruction associated with fragile topology which serves as a versatile platform to explore the interplay between quantum geometry and many-body physics in flat band systems. In twisted bilayer photonic crystals, we develop a theoretical framework that incorporates both near-field interlayer coupling and far-field radiation on equal footing, identifying unique features extend photonic moiré physics beyond merely an analogue of electronic moiré systems. Turning to engineered perturbations of photonic lattices, we demonstrate that a density wave-like displacement of the air holes in a photonic graphene slab simultaneously controls the band dispersion, bulk topology, and far-field radiation. The perturbation folds the intrinsic flat band of photonic graphene above the light line, drives a tunable band inversion, and produces a Friedrich-Wintgen bound state in the continuum alongside Jackiw-Rebbi interface states that inherit the flatness of the bulk band. Finally, we show that the bulk photovoltaic effect, which is forbidden in bulk transition metal dichalcogenides by inversion symmetry, can be activated and enhanced for chiral photodetection by patterning the material surface with a chiral metasurface. The metasurface engineers a symmetry-broken near-field environment that unlocks the geometric photocurrent intrinsic to the bulk material without modifying its crystal structure. Taken together, these works establish band engineering in structured photonic systems as a coherent and versatile research program, demonstrating that the interplay between geometry, symmetry, and quantum geometry in photonic crystals provides a rich design space for controlling light and its interactions with matter

Notes:

Source: Dissertations Abstracts International, Volume: 87-12, Section: B.

Advisors: Agarwal, Ritesh Committee members: Kane, Charles L.; Mele, Eugene J.; Feng, Liang

Ph.D. University of Pennsylvania 2026

Vendor supplied data

Local Notes:

School code: 0175

ISBN:

9798247973423

Access Restriction:

Restricted for use by site license