Efficient perturbative framework for coupling of radiative and guided modes in nearly periodic surfaces
We present a semi-analytical framework for computing the coupling of radiative and guided waves in slowly varying (nearly uniform or nearly periodic) surfaces, which is especially relevant to the exploitation of nonlocal effects in large-area metasurfaces. Our framework bridges a gap in the theory o...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Published: |
Massachusetts Institute of Technology
2023
|
| Online Access: | https://hdl.handle.net/1721.1/151257 |
| _version_ | 1826213191470809088 |
|---|---|
| author | Fisher, Sophie E. |
| author2 | Johnson, Steven G. |
| author_facet | Johnson, Steven G. Fisher, Sophie E. |
| author_sort | Fisher, Sophie E. |
| collection | MIT |
| description | We present a semi-analytical framework for computing the coupling of radiative and guided waves in slowly varying (nearly uniform or nearly periodic) surfaces, which is especially relevant to the exploitation of nonlocal effects in large-area metasurfaces. Our framework bridges a gap in the theory of slowly varying surfaces: aside from brute-force numerical simulations, current approximate methods can model either guided or radiative waves, but cannot easily model their coupling. We solve this problem by combining two methods: the locally periodic approximation, which approximates radiative scattering by composing a set of periodic scattering problems, and spatial coupled-wave theory, which allows the perturbative modeling of guided waves using an eigenmode expansion. We derive our framework for both nearly uniform and nearly periodic surfaces, and we validate each case against brute-force finite-difference time-domain simulations, which show increasing agreement as the surface varies more slowly. |
| first_indexed | 2024-09-23T15:44:45Z |
| format | Thesis |
| id | mit-1721.1/151257 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T15:44:45Z |
| publishDate | 2023 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/1512572023-08-01T03:09:43Z Efficient perturbative framework for coupling of radiative and guided modes in nearly periodic surfaces Fisher, Sophie E. Johnson, Steven G. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science We present a semi-analytical framework for computing the coupling of radiative and guided waves in slowly varying (nearly uniform or nearly periodic) surfaces, which is especially relevant to the exploitation of nonlocal effects in large-area metasurfaces. Our framework bridges a gap in the theory of slowly varying surfaces: aside from brute-force numerical simulations, current approximate methods can model either guided or radiative waves, but cannot easily model their coupling. We solve this problem by combining two methods: the locally periodic approximation, which approximates radiative scattering by composing a set of periodic scattering problems, and spatial coupled-wave theory, which allows the perturbative modeling of guided waves using an eigenmode expansion. We derive our framework for both nearly uniform and nearly periodic surfaces, and we validate each case against brute-force finite-difference time-domain simulations, which show increasing agreement as the surface varies more slowly. S.M. 2023-07-31T19:26:29Z 2023-07-31T19:26:29Z 2023-06 2023-07-13T14:20:55.329Z Thesis https://hdl.handle.net/1721.1/151257 0000-0002-7276-7257 Attribution 4.0 International (CC BY 4.0) Copyright retained by author(s) https://creativecommons.org/licenses/by/4.0/ application/pdf Massachusetts Institute of Technology |
| spellingShingle | Fisher, Sophie E. Efficient perturbative framework for coupling of radiative and guided modes in nearly periodic surfaces |
| title | Efficient perturbative framework for coupling of radiative and
guided modes in nearly periodic surfaces |
| title_full | Efficient perturbative framework for coupling of radiative and
guided modes in nearly periodic surfaces |
| title_fullStr | Efficient perturbative framework for coupling of radiative and
guided modes in nearly periodic surfaces |
| title_full_unstemmed | Efficient perturbative framework for coupling of radiative and
guided modes in nearly periodic surfaces |
| title_short | Efficient perturbative framework for coupling of radiative and
guided modes in nearly periodic surfaces |
| title_sort | efficient perturbative framework for coupling of radiative and guided modes in nearly periodic surfaces |
| url | https://hdl.handle.net/1721.1/151257 |
| work_keys_str_mv | AT fishersophiee efficientperturbativeframeworkforcouplingofradiativeandguidedmodesinnearlyperiodicsurfaces |