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In-Depth Information
found that the cylindrical geometry is less sensitive to the material
dissipation in comparison with the spherical geometry. In contrast
to the spherical nanostructures, all surface plasmon resonances in
small cylindrical metallic structures appear at the same frequency
corresponding to the value
ε
=−
1. This permits the scaling
and allows finding the intricate interconnection between near-field
distributionandfar-fieldscattering.Theattractivepropertyofsmall
plasmonic structures is the coexistence of the Fano resonance and
singular optics effects that allow to control optical vortices at the
nanoscale, with the size of vortices being two orders of magnitude
smallerthantheconventionalvorticesdiscussedpreviously[14,24].
As we mentioned above, the realization of the “nano-Fano”
plasmonic structures requires materials with weak dissipation. In
addition to natural low loss materials such as K, Na, and Al, a
promising way is to synthesize new weakly dissipative materials
such as alloys [25]. Another approach is to compensate losses
by employing the concepts of active plasmonics [26] or to use
anisotropyeffects[22,27].Realizationofextremelysmallstructures
with a pronounced Fano resonance is very attractive for various
applications in the data storage technology, nanosensors, and
topological optics.
Acknowledgments
We thank Drs. G. Vienne, R. Bakker, and A. Desyatnikov for
useful discussions. This work was supported by the Agency for
Science, Technology and Research (A*STAR) of Singapore: SERC
MetamaterialsProgramonSuperlens,grantno.0921540099;SERC
grant no. TSRP-1021520018; the grant no. JCOAG03-FG04-2009
from the Joint Council of A*STAR. The work of AEM and YSK was
supported by the Australian Research Council.
References
1. B. Luk'yanchuk, N. I. Zheludev, S. A. Maier, N. J. Halas, P. Nordlander,
H. Giessen, and T. C. Chong, The Fano resonance in plasmonic
nanostructures and metamaterials,
Nat. Mater
.
9
, 707 (2010).
