Nanofocusing in critically coupled nanogap waveguide resonators
File(s)
Author(s)
Type
Journal Article
Abstract
Coupling between optical antenna resonances is a powerful way to control the distribution of light in nanoscale systems. When the strength of coupling is fine-tuned against resonance loss, a critical coupling condition is often met, where energy can be efficiently directed between the system’s components. In this work, we use this concept to nanofocus optical energy into the 50 nm gap of a waveguide resonator, which on its own cannot be excited by external illumination. Light couples to the waveguide antenna via Fano interference with a bar antenna dimer. As a composite antenna, the shifting of the dimer relative to the waveguide resonator enables the precise tuning of their mutual coupling. We find a critical coupling condition where light is maximally focused into the waveguide’s gap corresponding to unity coupling cooperativity. Our interpretation of critical-coupling-induced nanofocusing is supported by the simultaneous maximization of both second and third harmonic generation at the critical condition.
Date Issued
2024-07-17
Date Acceptance
2024-06-03
Citation
ACS Photonics, 2024, 11 (7), pp.2836-2842
ISSN
2330-4022
Publisher
American Chemical Society
Start Page
2836
End Page
2842
Journal / Book Title
ACS Photonics
Volume
11
Issue
7
Copyright Statement
© 2024 The Authors. Published by American Chemical Society. This publication is licensed under
CC-BY 4.0 .
CC-BY 4.0 .
License URL
Identifier
https://pubs.acs.org/doi/10.1021/acsphotonics.4c00961
Subjects
2ND-HARMONIC GENERATION
ABSORPTION
critical coupling
ELECTROMAGNETICALLY INDUCED TRANSPARENCY
Fano resonance
FANO RESONANCES
FIELD ENHANCEMENT
LIGHT
Materials Science
Materials Science, Multidisciplinary
nanofocusing
nanophotonics
Nanoscience & Nanotechnology
nonlinearoptics
Optics
PHASE
Physical Sciences
Physics
Physics, Applied
Physics, Condensed Matter
PLASMONIC ANALOG
SCATTERING
Science & Technology
Science & Technology - Other Topics
SYMMETRY
Technology
waveguide resonator
Publication Status
Published
Date Publish Online
2024-06-13