A sharp-tipped gold nanocone and the vertically aligned metallic tip of a near-field optical microscope together form a three-dimensional optical antenna with a highly controllable gap. Confocal measurements with different laser modes show the efficient axial excitation of the cones with a longitudinally polarized field. In the antenna configuration, extremely strong field enhancement up to a factor of 100 is obtained by tuning the gap between the two sharp tips down to few nanometers.

Articles you may be interested inFabrication of ultra-high-density nanodot array patterns (∼3 Tbits/in.2) using electron-beam lithography J. Vac. Sci. Technol. B 29, 061602 (2011); 10.1116/1.3646469Electron-beam lithography for thick refractive optical elements in SU-8

No abstract

No abstract

No abstract

The partial thermodynamic functions Z~Li and Z~Li for LixTil.0sS 2 (0.13 ~ x a 0.97) and Li0.9sCoO 2 were obtained from EMF-temperature measurements (T = -30-20°C). For LixTil.oaS2, the x-dependence of these quantities is discussed in relation to a semiempirical expression for the EMF-x relation. The electronic component of the thermoelectric power in LixTil.0aS 2 (0 ~ x ~ 0.97, T = 50-200°C) and LixCoO 2 (0.20 ~ x ~ 1.00, T = 30-400°C) was determined. From the sign of the (electronic) Seebeck coefficient it followed that LixTil.03S 2 is a n-type and LixCoO 2 a ptype electronic conductor. The influence of the amount of inserted lithium and temperature dependence on the Seebeck coefficient is discussed. A new method to determine the ionic heat of transport directly from the ionic Seebeck coefficient was developed. This method was applied to LixTil.oaS 2 (0.61 ~ x ~ 0.97, T = -30-30°C). The heat of transport is much smaller than the activation enthalpy for Li+-conduction, indicating a high ionic polaron binding energy. Thermogravimetric analysis indicates that LixCoO 2 with x < 1 decomposes to LilCoO2 and Co203 at temperatures higher than 80°C. This is sustained by the data for the electronic Seebeck coefficient. Also the thermodynamic, thermoelectric and kinetic data of LixTil.03S 2 are critically compared with those of AgxTiS 2.

No abstract

No abstract