Nano-antennas

In order to prove the concept, the nano-antenna characterization had to be performed on a suitable device. The metal chosen was silver because of its favourable plasmonic properties in the visible spectmm [39]. The optimum parameters for the nano-antennas were calculated according to literature [34],... 

Fig. 1.20 The hologram design consist of four steps the digital creation of two independent images for each polarisation, the retrieval of independent diffraction patterns, the nano-antenna sampling of the fringes and finally the blending of both sampled designs...

The nano-antennas where fabricated on top of a 200 nm silicon dioxide layer on a standard silicon wafer. The substrate was spin coated with high resolution positive PMMA 950 K resist and electron beam lithography was used to define the nano-antenna structures. After exposure, the samples where developed in a M1BK 1PA solution with a 1 3 composition. Finally, silver was thermally evaporated and Ufted-off to remove of the unwanted residual metal areas. The total number of nano-antennas created was 6.25 x 10 distributed over an area of 2.13 mm. Although the final array of nano-antennas was laid on top of a dielectric layer of silicon dioxide, the silicon substrate obstructed the transmitted light. In Fig. 1.21, SEM pictures at different magnifications show the obtained results through this process. The two transversal nano-antennas in an L shape form a... 

L. Li, S. Fang Lim, A.A. Puretzky, R. Riehn, H.D. HaUen, Near-field enhanced ultraviolet resonance Raman spectroscopy using aluminum bow-tie nano-antenna. Appl. Phys. Lett. 101, 113116(2012)... 

We have seen that, in photosynthetic bacteria, visible light is harvested by the antenna complexes, from which the collected energy is funnelled into the special pair in the reaction centre. A series of electron-transfer steps occurs, producing a charge-separated state across the photosynthetic membrane with a quantum efficiency approaching 100%. The nano-sized structure of this solar energy-conversion system has led researchers over the past two decades to try to imitate the effects that occur in nature. 

Chen G, Wu J, Lu QJ, Guitierrez HRH, Xiong Q, Pellen ME, Petko JS, Werner DH, Eklund PC (2008) Optical antenna effects in semiconducting nanowires. Nano Lett 8 1341-1346... 

For the future work, elastomer tunable optofluidic devices are expected to extend into the nano-optics or nanofluidic fields. Several tunable nano-optical antenna devices fabricated on a stretchable PDMS substrate have been demonstrated recently. Combining elastomer-based micro/nano-devices with nanoplasmonic elements can be interesting for molecule-level imaging and spectroscopy. A tunable elastic nanofluidic channel was demonstrated recently on a PDMS chip for nanoparticle separation and molecule trapping [12]. One of the challenges of PDMS-based tunable nano-devices is to realize the high accuracy in control. High-precision control of PDMS-based tunable structures could be realized by very fine pneumatic actuation or connection to a piezo-actuator. 

Semiconductor nano element devices show great promise, potentially outperforming standard electrical, opt-electrical, and sensor- etc. semiconductor devices. These devices can use certain nano element specific properties, 2-D, 1-D, or 0-D quantum confinement, flexibility in axial material variation due to less lattice match restrictions, antenna properties, ballistic transport, wave guiding properties etc. Furthermore, in order to design first rate semiconductor devices from nanoelements, transistors, light emitting diodes, semiconductor lasers, and sensors, and to fabricate efficient contacts, particularly with low access resistance, to such devices, the ability to dope and fabricate doped regions is cracial [66, 67]. 

A major improvement was reached by substituting [Ru(bpy)3] with the tetranuclear dendrimeric derivative [Ru (p-2,3-dpp)Ru(bpy)2 3] " " (4 in Fig. 2). Using this antenna in combination with citrate-stabilized nano-Ir02 (20 nm) and Na2S20g as sacrificial agent upon irradiation (k> 550 nm), a 6-fold increase in oxygen evolution is observed, together with an overall quantum yield 0(02) of 0.015. ... 

Sudeep PK, Ipe BI, Thomas KG, George MV (2002) Fullerene-functionalized GNPs. A self-assembled photoactive antenna-metal nanocore assembly. Nano Lett 2 29-35... 

A first step towards such a nano-FTIR system has recently been taken using a thermal IR sources and a scanning infrared antenna [82]. These initial measurements were limited in spectral range to about 750-1250 cm but they show better than 100nm resolution and more importantly that the idea of broadband nano-FTIR could indeed work. Several... 

Shankar, K., Bandara, J., Paulose, M., Wietasch, H., Varghese, O.K., Mor, G.K., LaTempa, T.J., Thelakkat, M. Grimes, C.A. Highly efficient solar cells using Ti02 nanotube arrays sensitized with a donor-antenna Aye. Nano Lett. 8 6 (2008), pp. 1654-1659. 

M. Mivelle, T.S. van Zanten, L. Neumann, N.F. van Hulst, M.F. Garcia-Parajo, Ultrabright bowtie nanoaperture antenna probes studied by single molecule fluorescence. Nano Lett. 12, 5972-5978 (2012)... 

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