13 Spinoptics in Plasmonics
475
−
σ
+
σ
z
GM
r
E
Circular
polarizer
(b)
(d)
(e)
(c)
(a)
y
x
GM
z
E
Fig. 13.8 Far-field analysis of the light scattered from the element. a The E z component distribution
of the guided mode and the instantaneous transverse vectorial field (E r ). b, c measured and d, e
calculated intensity distributions of the light scattered to the far-field, for light transmitted through
right-handed b, d and left-handed c, e circular polarizer. Reprinted with permission from Ref. [34].
Copyright 2009 American Chemical Society
13.4 Plasmonic Aharonov-Bohm Effect
As it was showed in previous section the rotation of the local anisotropy axis related
to the slit curvature entails correction of the momentum term in the wave equation,
which results in a spiral geometric phase. The geometric phase of the surface plasmons can be directly observed via the interference pattern in the near-field by means
of near-field scanning optical microscope (NSOM) [46]. The observed effect will be
analyzed using the analogy of the scattering of electrons from a topological defect
in the Aharonov-Bohm (AB) effect [47]. In order to observe the surface plasmon
interference in the near-field a structure onto glass substrate was chosen consisting
of thin (120 nm) gold film with annular aperture (inner and outer radii of the aperture
are 365 and 525 nm, respectively). The 320 nm-wide slit has been milled in the proximity of the annular aperture to provide a reference wavefront for the interference
475
−
σ
+
σ
z
GM
r
E
Circular
polarizer
(b)
(d)
(e)
(c)
(a)
y
x
GM
z
E
Fig. 13.8 Far-field analysis of the light scattered from the element. a The E z component distribution
of the guided mode and the instantaneous transverse vectorial field (E r ). b, c measured and d, e
calculated intensity distributions of the light scattered to the far-field, for light transmitted through
right-handed b, d and left-handed c, e circular polarizer. Reprinted with permission from Ref. [34].
Copyright 2009 American Chemical Society
13.4 Plasmonic Aharonov-Bohm Effect
As it was showed in previous section the rotation of the local anisotropy axis related
to the slit curvature entails correction of the momentum term in the wave equation,
which results in a spiral geometric phase. The geometric phase of the surface plasmons can be directly observed via the interference pattern in the near-field by means
of near-field scanning optical microscope (NSOM) [46]. The observed effect will be
analyzed using the analogy of the scattering of electrons from a topological defect
in the Aharonov-Bohm (AB) effect [47]. In order to observe the surface plasmon
interference in the near-field a structure onto glass substrate was chosen consisting
of thin (120 nm) gold film with annular aperture (inner and outer radii of the aperture
are 365 and 525 nm, respectively). The 320 nm-wide slit has been milled in the proximity of the annular aperture to provide a reference wavefront for the interference