Plasmon-Interband Coupling in Nickel Nanoantennas
Artikel i vetenskaplig tidskrift, 2014

Plasmonic excitations are usually attributed to the free electron response at visible frequencies in the classic plasmonic metals Au and Ag. However, the vast majority of metals exhibit spectrally localized interband transitions or broad interband transition backgrounds in the energy range of interest for nanoplasmonics. Nevertheless, the interaction of interband transitions with localized plasmons in optical nanoantennas has hitherto received relatively little attention, probably because interband transitions are regarded as highly unwanted due to their strong damping effect on the localized plasmons. However, with an increasing number of metals (beyond Au and Ag) being considered for nanoplasmonic applications such as hydrogen sensing (Pd), UV-SERS (Al), or magnetoplasmonics (Ni, Fe, Co), a deeper conceptual understanding of the interactions between a localized plasmon mode and an interband transition is very important. Here, as a generic example, we examine the interaction of a localized (in energy space) interband transition with spectrally tunable localized plasmonic excitations and unearth the underlying physics in a phenomenological approach for the case of Ni disk nanoantennas. We find that plasmon interband interactions can be understood in the classical picture of two coupled harmonic oscillators, exhibiting the typical energy anticrossing fingerprint of a coupled system approaching the strong-coupling regime.

strong coupling

interband transition

nickel

localized surface plasmon resonance

nanoantenna

Författare

Zhaleh Pirzadeh Irannezhad

Chalmers, Teknisk fysik, Bionanofotonik

Tavakol Pakizeh

Chalmers, Teknisk fysik, Bionanofotonik

Vladimir Miljkovic

Chalmers, Teknisk fysik, Bionanofotonik

Christoph Langhammer

Chalmers, Teknisk fysik, Kemisk fysik

Alexander Dmitriev

Chalmers, Teknisk fysik, Bionanofotonik

ACS Photonics

2330-4022 (eISSN)

Vol. 1 3 158-162

Ämneskategorier

Annan teknik

DOI

10.1021/ph4000339