Significant loss suppression and large induced chirality via cooperative near- and far-field coupling in plasmonic dimer nanoantennas

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Main Authors: Luo, Xiaoqing, Huang, Rixing, Lei, Dangyuan, Li, Guangyuan
Format: Preprint
Published: 2024
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_version_ 1866929600939950080
author Luo, Xiaoqing
Huang, Rixing
Lei, Dangyuan
Li, Guangyuan
author_facet Luo, Xiaoqing
Huang, Rixing
Lei, Dangyuan
Li, Guangyuan
contents Plasmonic nanoantennas containing nano-gaps support "hotspots" for greatly enhanced light-matter interactions, but suffer from inherent high losses, a long-standing issue that hinders practical applications. Here we report a strategy to significantly suppress the losses of plasmonic dimer nanoantennas. Specifically, by introducing the concept of cooperative near- and far-field coupling, we observed an unprecedented transition from the weak coupling of localized resonances to strong coupling of collective (nonlocal) resonances, showing robustness to the gap distance between the dimer. We develop a generalized lattice sum approximation model to describe this transition and reveal its origins: the off-diagonal element of the anisotropic polarizability tensor due to near-field coupling, and the anisotropic lattice sums due to far-field coupling. This strong coupling leads to loss-suppressed plasmonic resonances with large modulation depths and meanwhile extremely high measured quality factors up to 3120 in the near-infrared regime, exceeding the record in the near infrared regime. Additionally, high-$Q$ and large chiroptical responses can also be induced for achiral planar dimers under the critical coupling condition. This work paves an avenue toward extremely low-loss plasmonic devices, either chiral or not, for diverse important applications.
format Preprint
id arxiv_https___arxiv_org_abs_2411_15029
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Significant loss suppression and large induced chirality via cooperative near- and far-field coupling in plasmonic dimer nanoantennas
Luo, Xiaoqing
Huang, Rixing
Lei, Dangyuan
Li, Guangyuan
Optics
Applied Physics
Plasmonic nanoantennas containing nano-gaps support "hotspots" for greatly enhanced light-matter interactions, but suffer from inherent high losses, a long-standing issue that hinders practical applications. Here we report a strategy to significantly suppress the losses of plasmonic dimer nanoantennas. Specifically, by introducing the concept of cooperative near- and far-field coupling, we observed an unprecedented transition from the weak coupling of localized resonances to strong coupling of collective (nonlocal) resonances, showing robustness to the gap distance between the dimer. We develop a generalized lattice sum approximation model to describe this transition and reveal its origins: the off-diagonal element of the anisotropic polarizability tensor due to near-field coupling, and the anisotropic lattice sums due to far-field coupling. This strong coupling leads to loss-suppressed plasmonic resonances with large modulation depths and meanwhile extremely high measured quality factors up to 3120 in the near-infrared regime, exceeding the record in the near infrared regime. Additionally, high-$Q$ and large chiroptical responses can also be induced for achiral planar dimers under the critical coupling condition. This work paves an avenue toward extremely low-loss plasmonic devices, either chiral or not, for diverse important applications.
title Significant loss suppression and large induced chirality via cooperative near- and far-field coupling in plasmonic dimer nanoantennas
topic Optics
Applied Physics
url https://arxiv.org/abs/2411.15029