Biomedical Engineering Reference
In-Depth Information
simulation yielded a reduction of a factor of 10; (ii) our optics can
collect maximum 50% of the re-emitted light resulting in another
factor of 2; (iii) only a fraction of the nanorod emission can be
expectedtocoupletotheplasmonsinthenanowire,becausetherod
covered area is with 1
μ
m
2
rather large. From (i) and (ii) we obtain
a lower limit of the reduction factor of 20, and the difference to the
observed factor can bewell justified by point (iii).
Finally we note that experiments on nanowires without
nanorods showed that the laser spot with 488 nm wavelength
focused on one end of the nanowire did not result in any light
emission at the opposite end.
15.3.5
Conclusion and Outlook
We demonstrated the coupling of the exciton emission of nanorods
positioned at the end a Au nanowire to propagating SP modes
and the detection of the outcoupled light at the opposite nanowire
end. For the process the excitation laser wavelength was tuned to
the absorption of the nanorod material in the UV-blue spectral
band, while the coupling occurred in the red triggered by the
nanorod emission. This approach enabled the decoupling of the
spectral bands of laser excitation and light transmission thanks
to the core-shell architecture of the nanorods. The EBL defined
fabrication allows for precise control over the position and shape
oftheAunanowire.Thiswillallowfurtherinvestigationswithmore
complex geometries that promise deeper insight into the coupling
phenomena.
15.4 Plasmonics SERS Devices
Recently, there has been much attention for surface enhanced
Raman scattering (SERS) because of its potential application in
various fields [57-60]. The generation of SPs, due to the interaction
of light and metal surface electrons, causes the focusing of hot
spots, which depend on size, shape, interparticle gap, dielectric
constant of the surrounding medium [61-65]. These parameters
should be chosen carefully in order to achieve significant plasmon
