424
A. Pors et al.
(c)
(a)
(b)
(d)
Fig. 11.12 a Sketch of nanobrick system. b Scattering cross section at three angles Ω for L 2 =
140 nm. c Normalized experimental reflection spectra for seven dififferent values of Ω. The inset
shows an electric microscopy image of the fabricated 400 nm-period array consisting of ∼50 nm high
gold bricks with short and long axes of ∼100 nm and 150 nm, respectively. d Normalized reflection
from the array as a function of analyzer angle w.r.t. the long axis of the brick for ϕ = 780 nm.
The reflection in c and d was normalized using the reflectivity from a ∼300 nm-thick gold film
and weighted with the calculated reflectivity by using gold optical constants. Reproduced with
permission from Ref. [15]. ©The Optical Society Of America 2011
nanoantennas with the same cross section of 50 × 50 nm 2 but of different length (i.e.,
orthogonal DEDs). Note that it is possible to excite individual plasmonic resonances
by choosing the angle of polarization, Ω, of the incident linearly polarized wave to
either Ω = 0 ◦ or Ω = 90 ◦ (Fig. 11.11b). For intermediate angles, both resonances
are excited, which allows us to construct a quarter-wave plate by properly choosing
the length of the nanoantennas (detuning) and Ω (influencing the relative strength
of DEDs). The right choice of length is illustrated in Fig. 11.11c for Ω = 45 ◦ when
the short axis is fixed at L 1 = 260 nm and the long axis, L 2 , is slightly varied.
The figure depicts the phase difference between the y- and x-component of the scattered electric field (E sc,y and E sc,x ) along the -z-axis in the far field showing that
for L 2 = 338 nm the phase difference is ∼ η/2 at ϕ = 1520 nm. At this wavelength, the minimum observed in the scattering cross section is related to plasmonic
currents induced in both nanoantennas (Fig. 11.11f), whereas the scattering cross
section maxima at wavelengths ϕ = 1370 nm and ϕ = 1640 nm are related to plasmonic currents induced only in the vertical (Fig. 11.11e) and horizontal (Fig. 11.11g)
A. Pors et al.
(c)
(a)
(b)
(d)
Fig. 11.12 a Sketch of nanobrick system. b Scattering cross section at three angles Ω for L 2 =
140 nm. c Normalized experimental reflection spectra for seven dififferent values of Ω. The inset
shows an electric microscopy image of the fabricated 400 nm-period array consisting of ∼50 nm high
gold bricks with short and long axes of ∼100 nm and 150 nm, respectively. d Normalized reflection
from the array as a function of analyzer angle w.r.t. the long axis of the brick for ϕ = 780 nm.
The reflection in c and d was normalized using the reflectivity from a ∼300 nm-thick gold film
and weighted with the calculated reflectivity by using gold optical constants. Reproduced with
permission from Ref. [15]. ©The Optical Society Of America 2011
nanoantennas with the same cross section of 50 × 50 nm 2 but of different length (i.e.,
orthogonal DEDs). Note that it is possible to excite individual plasmonic resonances
by choosing the angle of polarization, Ω, of the incident linearly polarized wave to
either Ω = 0 ◦ or Ω = 90 ◦ (Fig. 11.11b). For intermediate angles, both resonances
are excited, which allows us to construct a quarter-wave plate by properly choosing
the length of the nanoantennas (detuning) and Ω (influencing the relative strength
of DEDs). The right choice of length is illustrated in Fig. 11.11c for Ω = 45 ◦ when
the short axis is fixed at L 1 = 260 nm and the long axis, L 2 , is slightly varied.
The figure depicts the phase difference between the y- and x-component of the scattered electric field (E sc,y and E sc,x ) along the -z-axis in the far field showing that
for L 2 = 338 nm the phase difference is ∼ η/2 at ϕ = 1520 nm. At this wavelength, the minimum observed in the scattering cross section is related to plasmonic
currents induced in both nanoantennas (Fig. 11.11f), whereas the scattering cross
section maxima at wavelengths ϕ = 1370 nm and ϕ = 1640 nm are related to plasmonic currents induced only in the vertical (Fig. 11.11e) and horizontal (Fig. 11.11g)