The growing demand for energy-efficient optical information processing motivates compact nonlinear photonic devices that can operate at low power. Silicon photonics is a mature platform for linear optical functions, but nonlinear operation remains challenging because of its weak Kerr response, two-photon absorption at telecommunication wavelengths, and limited compatibility with deeply subwavelength plasmonic confinement. This thesis computationally investigates epsilon-near-zero thin films integrated into plasmonic waveguide architectures as a route toward stronger light–matter interaction in compact nonlinear devices.
Two waveguide geometries are examined: a hybrid metal-insulator-metal plasmonic slab waveguide incorporating an ultrathin indium tin oxide epsilon-near-zero layer (5–50 nm), and a dielectric-loaded surface plasmon polariton waveguide. Finite element method simulations were performed in COMSOL Multiphysics 6.2 using the Wave Optics Module. Parametric sweeps over epsilon-near-zero layer thickness, metal cladding material, and operating wavelength were used to evaluate effective nonlinear response, propagation loss, and normalized loss-adjusted figures of merit.
For the metal-insulator-metal geometry, thinner epsilon-near-zero layers produced larger effective nonlinear coefficients, with the 5 nm silver–indium tin oxide case reaching 2.66 rad/(W·m) at 1561.1 nm. This enhancement also increased propagation loss, so the useful design space is governed by a trade-off between confinement and attenuation. In the dielectric-loaded surface plasmon polariton geometry, the nonlinear overlap metric peaked near 50 nm indium tin oxide thickness, while the normalized loss-adjusted figure of merit favored thinner layers because loss increased with indium tin oxide thickness.
The simulations identify silver–indium tin oxide metal-insulator-metal structures as strong candidates for high-confinement nonlinear response and dielectric-loaded surface plasmon polariton structures as a more fabrication-accessible alternative with different loss and overlap trade-offs. The main limitation of the present model is that the nonlinear coefficient of indium tin oxide was treated as wavelength independent, so the expected resonant enhancement near the epsilon-near-zero crossing was not fully captured. These results provide a computational baseline for future epsilon-near-zero-integrated nonlinear photonic devices and for follow-up simulations using wavelength-dependent nonlinear material parameters.
","abstract_html":"<p>The growing demand for energy-efficient optical information processing motivates compact nonlinear photonic devices that can operate at low power. Silicon photonics is a mature platform for linear optical functions, but nonlinear operation remains challenging because of its weak Kerr response, two-photon absorption at telecommunication wavelengths, and limited compatibility with deeply subwavelength plasmonic confinement. This thesis computationally investigates epsilon-near-zero thin films integrated into plasmonic waveguide architectures as a route toward stronger light–matter interaction in compact nonlinear devices.</p> <p>Two waveguide geometries are examined: a hybrid metal-insulator-metal plasmonic slab waveguide incorporating an ultrathin indium tin oxide epsilon-near-zero layer (5–50 nm), and a dielectric-loaded surface plasmon polariton waveguide. Finite element method simulations were performed in COMSOL Multiphysics 6.2 using the Wave Optics Module. Parametric sweeps over epsilon-near-zero layer thickness, metal cladding material, and operating wavelength were used to evaluate effective nonlinear response, propagation loss, and normalized loss-adjusted figures of merit.</p> <p>For the metal-insulator-metal geometry, thinner epsilon-near-zero layers produced larger effective nonlinear coefficients, with the 5 nm silver–indium tin oxide case reaching 2.66 rad/(W·m) at 1561.1 nm. This enhancement also increased propagation loss, so the useful design space is governed by a trade-off between confinement and attenuation. In the dielectric-loaded surface plasmon polariton geometry, the nonlinear overlap metric peaked near 50 nm indium tin oxide thickness, while the normalized loss-adjusted figure of merit favored thinner layers because loss increased with indium tin oxide thickness.</p> <p>The simulations identify silver–indium tin oxide metal-insulator-metal structures as strong candidates for high-confinement nonlinear response and dielectric-loaded surface plasmon polariton structures as a more fabrication-accessible alternative with different loss and overlap trade-offs. The main limitation of the present model is that the nonlinear coefficient of indium tin oxide was treated as wavelength independent, so the expected resonant enhancement near the epsilon-near-zero crossing was not fully captured. These results provide a computational baseline for future epsilon-near-zero-integrated nonlinear photonic devices and for follow-up simulations using wavelength-dependent nonlinear material parameters.</p>","abstract_has_math":false,"creators":["Le, Kevin Tran"],"institution":null,"degree_name":null,"degree_level":"Thesis","degree_discipline":"Electrical Engineering and Computer Science","degree_department":null,"school":null,"contributors":["Mark C. Harrison, Ph.D.","Mohamed Allali, Ph.D.","Maryam Etezadbrojerdi, Ph.D."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-05-01T07:00:00Z","date_published":"2026-05-01T07:00:00Z","updated_at":"2026-07-24T01:38:47Z","subjects":["nonlinear optics","epsilon-near-zero (ENZ)","plasmonics","nanophotonics","thin films","metamaterials","Atomic, Molecular and Optical Physics","Computer Sciences","Condensed Matter Physics","Electrical and Computer Engineering","Electromagnetics and Photonics","Electronic Devices and Semiconductor Manufacturing","Engineering","Engineering Physics","Materials Science and Engineering","Nanoscience and Nanotechnology","Nanotechnology Fabrication","Other Computer Sciences","Physical Sciences and Mathematics","Physics","Semiconductor and Optical Materials"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.chapman.edu/eecs_theses/12","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mark C. Harrison, Ph.D.","Mohamed Allali, Ph.D.","Maryam Etezadbrojerdi, Ph.D."]},{"key":"dc:creator","label":"Author","values":["Le, Kevin Tran"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering and Computer Science"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["nonlinear optics","epsilon-near-zero (ENZ)","plasmonics","nanophotonics","thin films","metamaterials","Atomic, Molecular and Optical Physics","Computer Sciences","Condensed Matter Physics","Electrical and Computer Engineering","Electromagnetics and Photonics","Electronic Devices and Semiconductor Manufacturing","Engineering","Engineering Physics","Materials Science and Engineering","Nanoscience and Nanotechnology","Nanotechnology Fabrication","Other Computer Sciences","Physical Sciences and Mathematics","Physics","Semiconductor and Optical Materials"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.chapman.edu/eecs_theses/12"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The growing demand for energy-efficient optical information processing motivates compact nonlinear photonic devices that can operate at low power. Silicon photonics is a mature platform for linear optical functions, but nonlinear operation remains challenging because of its weak Kerr response, two-photon absorption at telecommunication wavelengths, and limited compatibility with deeply subwavelength plasmonic confinement. This thesis computationally investigates epsilon-near-zero thin films integrated into plasmonic waveguide architectures as a route toward stronger light–matter interaction in compact nonlinear devices.
Two waveguide geometries are examined: a hybrid metal-insulator-metal plasmonic slab waveguide incorporating an ultrathin indium tin oxide epsilon-near-zero layer (5–50 nm), and a dielectric-loaded surface plasmon polariton waveguide. Finite element method simulations were performed in COMSOL Multiphysics 6.2 using the Wave Optics Module. Parametric sweeps over epsilon-near-zero layer thickness, metal cladding material, and operating wavelength were used to evaluate effective nonlinear response, propagation loss, and normalized loss-adjusted figures of merit.
For the metal-insulator-metal geometry, thinner epsilon-near-zero layers produced larger effective nonlinear coefficients, with the 5 nm silver–indium tin oxide case reaching 2.66 rad/(W·m) at 1561.1 nm. This enhancement also increased propagation loss, so the useful design space is governed by a trade-off between confinement and attenuation. In the dielectric-loaded surface plasmon polariton geometry, the nonlinear overlap metric peaked near 50 nm indium tin oxide thickness, while the normalized loss-adjusted figure of merit favored thinner layers because loss increased with indium tin oxide thickness.
The simulations identify silver–indium tin oxide metal-insulator-metal structures as strong candidates for high-confinement nonlinear response and dielectric-loaded surface plasmon polariton structures as a more fabrication-accessible alternative with different loss and overlap trade-offs. The main limitation of the present model is that the nonlinear coefficient of indium tin oxide was treated as wavelength independent, so the expected resonant enhancement near the epsilon-near-zero crossing was not fully captured. These results provide a computational baseline for future epsilon-near-zero-integrated nonlinear photonic devices and for follow-up simulations using wavelength-dependent nonlinear material parameters.
"]},{"key":"dc:source","label":"Dc Source","values":["K. T. Le, \"Designing enhanced nonlinearity in plasmonic devices with epsilon-near-zero films,\" M. S. thesis, Chapman University, Orange, CA, 2026. https://doi.org/10.36837/chapman.000743"]},{"key":"dc:title","label":"Title","values":["Designing Enhanced Nonlinearity in Plasmonic Devices with Epsilon-Near-Zero Films"]}]}],"canonical_facts":{"dc:contributor":["Mark C. Harrison, Ph.D.","Mohamed Allali, Ph.D.","Maryam Etezadbrojerdi, Ph.D."],"dc:creator":["Le, Kevin Tran"],"dc:description.abstract":["The growing demand for energy-efficient optical information processing motivates compact nonlinear photonic devices that can operate at low power. Silicon photonics is a mature platform for linear optical functions, but nonlinear operation remains challenging because of its weak Kerr response, two-photon absorption at telecommunication wavelengths, and limited compatibility with deeply subwavelength plasmonic confinement. This thesis computationally investigates epsilon-near-zero thin films integrated into plasmonic waveguide architectures as a route toward stronger light–matter interaction in compact nonlinear devices.
Two waveguide geometries are examined: a hybrid metal-insulator-metal plasmonic slab waveguide incorporating an ultrathin indium tin oxide epsilon-near-zero layer (5–50 nm), and a dielectric-loaded surface plasmon polariton waveguide. Finite element method simulations were performed in COMSOL Multiphysics 6.2 using the Wave Optics Module. Parametric sweeps over epsilon-near-zero layer thickness, metal cladding material, and operating wavelength were used to evaluate effective nonlinear response, propagation loss, and normalized loss-adjusted figures of merit.
For the metal-insulator-metal geometry, thinner epsilon-near-zero layers produced larger effective nonlinear coefficients, with the 5 nm silver–indium tin oxide case reaching 2.66 rad/(W·m) at 1561.1 nm. This enhancement also increased propagation loss, so the useful design space is governed by a trade-off between confinement and attenuation. In the dielectric-loaded surface plasmon polariton geometry, the nonlinear overlap metric peaked near 50 nm indium tin oxide thickness, while the normalized loss-adjusted figure of merit favored thinner layers because loss increased with indium tin oxide thickness.
The simulations identify silver–indium tin oxide metal-insulator-metal structures as strong candidates for high-confinement nonlinear response and dielectric-loaded surface plasmon polariton structures as a more fabrication-accessible alternative with different loss and overlap trade-offs. The main limitation of the present model is that the nonlinear coefficient of indium tin oxide was treated as wavelength independent, so the expected resonant enhancement near the epsilon-near-zero crossing was not fully captured. These results provide a computational baseline for future epsilon-near-zero-integrated nonlinear photonic devices and for follow-up simulations using wavelength-dependent nonlinear material parameters.
"],"dc:identifier":["https://digitalcommons.chapman.edu/eecs_theses/12"],"dc:source":["K. T. Le, \"Designing enhanced nonlinearity in plasmonic devices with epsilon-near-zero films,\" M. S. thesis, Chapman University, Orange, CA, 2026. https://doi.org/10.36837/chapman.000743"],"dc:subject":["nonlinear optics","epsilon-near-zero (ENZ)","plasmonics","nanophotonics","thin films","metamaterials","Atomic, Molecular and Optical Physics","Computer Sciences","Condensed Matter Physics","Electrical and Computer Engineering","Electromagnetics and Photonics","Electronic Devices and Semiconductor Manufacturing","Engineering","Engineering Physics","Materials Science and Engineering","Nanoscience and Nanotechnology","Nanotechnology Fabrication","Other Computer Sciences","Physical Sciences and Mathematics","Physics","Semiconductor and Optical Materials"],"dc:title":["Designing Enhanced Nonlinearity in Plasmonic Devices with Epsilon-Near-Zero Films"],"thesis:degree_discipline":["Electrical Engineering and Computer Science"],"thesis:degree_level":["Thesis"]},"updated_at":"2026-07-24T01:38:47Z"}