Proceedings Article | 16 February 2009
Proc. SPIE. 7223, Photonic and Phononic Crystal Materials and Devices IX
KEYWORDS: Gold, Nanostructures, Surface plasmons, Scattering, Metals, Photons, Light scattering, Laser scattering, Plasma enhanced chemical vapor deposition, Carbon nanotubes
In terms of operational bandwidth and speed, photonic components are superior to electronic ones. However, it is
difficult to control photons on nanoscale structures for data processing and interconnection. Nanophotonic device using
surface plasmon (SP) offers an ideal solution to combine the superior technical advantages of both photonics and
electronics on the same chip. The SP wavelength is much shorter than that of the exciting light, allowing the use of SP in
various techniques that overcome diffraction limits. In this paper, we report an interesting plasmonic effect, enhanced
backward scattering, by using a periodically-aligned carbon nanotube (CNT) array. The CNTs are grown on a
transparent glass substrate with an average diameter of 50 nm and a length of about 1 μm. To enhance the conductivity,
the CNTs are also coated with 10-nm Au layer by using E-beam CVD technique. By shining a laser beam to the CNT
array, we found that the scattering intensity is maximally enhanced at the backward incident direction. The enhanced
backward incident scattering is observed by using both periodic and nonperiodic CNT samples. The experimental results
suggest that the backward scattering effect is due to the SP excitation and coupling. The proposed technique exploiting
aligned carbon-nanotube arrays to manipulate surface plasmon will lead to useful optical features such as optical
antennae effects, retro-reflection, switching, wavelength add/drop multiplexing, and may be particularly useful for
optical sensing, smart target identification and optical wireless secure communication applications.
