Surface plasmon resonance on vicinity of gold-coated fiber tip

The possibility of excitation of Surface Plasmon Polaritons (SPP) in the vicinity of the tip of a gold covered optical fiber is investigated when the tip is in the medium with a certain dielectric permittivity. In the experiment the medium was a solution consisting of dimethyl sulfoxide and ethanol liquids in which, as a result of evaporation, a smooth changing of the dielectric permittivity of the solution was taking place. During the evaporation a peak of the power of output radiation was observed from the tip of the fiber, which is explained by the resonant excitation of SPR This mechanism of SPP excitation in the region of the tip of the optical waveguide opens up new possibilities for increasing the resolution of the nanometric scanning optical microscope and for creation of a new type of optochemical fiber sensors. (c) 2007 Elsevier B.V. All rights reserved.