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Asymmetric L-shaped resonant optical antennas with plasmon length tuning and high-electric field enhancement

Bralović, Nikola 1; Lemmer, Uli 1,2; Hussein, Mohamed 1
1 Lichttechnisches Institut (LTI), Karlsruher Institut für Technologie (KIT)
2 Institut für Mikrostrukturtechnik (IMT), Karlsruher Institut für Technologie (KIT)


L-shaped resonant optical antennas (ROAs) are low-symmetry plasmonic nanostructures with the unique ability to show two tunable resonances in the optical and near-infrared wavelength regions. The plasmon length of the so-called longitudinal dipolar fundamental plasmon mode of these asymmetric L-shaped ROAs can be used as plasmon resonance building blocks to design polarization-sensitive devices. This paper introduces and numerically analyzes a novel design of asymmetric L-shape ROAs. The reported design offers two resonance modes, i.e., bimodal longitudinal antenna resonance behavior with a high enhancement factor. These two resonances can be selectively excited by changing the linear polarization angle. It is found that the coupled L-shaped ROA with a very small 2 nm gap width exhibits field enhancements 40 and 147.3 on scale |ETOT|/|EIN| for the high energy and low energy resonance, respectively. The obtained results and the analysis open a new route for multiple plasmon resonance devices with ultra-high field enhancement that can be easily integrated with future nano-optical circuits with multiple operational frequencies.

Verlagsausgabe §
DOI: 10.5445/IR/1000160615
Veröffentlicht am 14.07.2023
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Lichttechnisches Institut (LTI)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 09.2023
Sprache Englisch
Identifikator ISSN: 0306-8919, 1572-817X
KITopen-ID: 1000160615
HGF-Programm 38.01.05 (POF IV, LK 01) Simulations, Theory, Optics and Analytics (STOA)
Erschienen in Optical and Quantum Electronics
Verlag Springer
Band 55
Heft 9
Seiten Art.-Nr.: 824
Vorab online veröffentlicht am 07.07.2023
Nachgewiesen in Scopus
Web of Science
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