Coupling Strength Can Control the Polarization Twist of a Plasmonic Antenna

The far-field polarization of the optical response of a plasmonic antenna can be tuned by subtly engineering of its geometry. In this paper, we develop design rules for nano antennas which enable the generation of circular polarized light via the excitation of circular plasmonic modes in the structure. Two initially orthogonal plasmonic modes are coupled in such a way that a rotational current is excited in the structure. Modifying this coupling strength from a weak to a strong regime controls the helicity of the scattered field. Finally, we introduce an original sensing approach that relies on the rotation of the incident polarization and demonstrates a sensitivity of 0.23 deg.nm(-1) or 33 deg.RIU-1, related to changes of mechanical dimensions and the refractive index, respectively.


Published in:
Nano Letters, 13, 9, 4575-4579
Year:
2013
Publisher:
Washington, Amer Chemical Soc
ISSN:
1530-6984
Keywords:
Laboratories:




 Record created 2014-02-17, last modified 2018-09-13


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