Wang, Jitong;
(2024)
Theoretical and computational investigation of active photonic
nanodevices exploiting bound states in the continuum.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
In this thesis, a comprehensive theoretical and computational study of the implementation of optical bound states in the continuum (BICs) in active photonic nanodevices is presented. The peculiar numerical and analytical methods described in this thesis facilitate the understanding of the underlying physics of resonant phenomena and nonlinear effects in artificial optical nanostructures, and thus advance the progress in the design and fabrication of photonic nanodevices with novel functionalities and enhanced optical response. High-harmonic generation, including second- and third-order frequency conversion processes, has been thoroughly studied in this dissertation via nonlinear dielectric metasurfaces and photonic crystal (PhC) slabs. Especially, the strong confinement and enhancement of light-matter interactions arising from BICs and guided-mode resonances have been examined in the proposed photonic designs, and the generated harmonic emissions from doubly resonant structures have been characterized by a semi-analytical model based on a modal expansion method. Moreover, two-dimensional materials, namely transition metal dichalcogenides, have been incorporated with BIC-governed dielectric metasurfaces to enhance nonlinear optical response from the atomically thin monolayer. Along with the study of enhanced nonlinearity, great efforts have also been spent in the topological analysis of BICs and BIC-like resonances above the diffraction limit to explore winding properties of far-field polarization in the momentum space and powerful manipulation of nonlinear vortex beams. The last part of the thesis was focused on the study of lasing action in active photonic nanodevices. In particular, utilizing the topological properties, BIC-governed quantum dot PhC slabs have been designed to generate and control single-beam and multi-beam laser emissions. The lasing action examined through the Fourier analysis demonstrates the promising functionality in vortex generation.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Theoretical and computational investigation of active photonic nanodevices exploiting bound states in the continuum |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10193753 |
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