Two-dimensional near-field intensity distribution of tapered fiber probes

The near-field intensity distribution perpendicular to the light-propagation direction was measured by photochemical processes on conjugated-polymer thin films. The shape of the distribution is elliptical, with the long axis along the direction of the incident polarization. The results are compared with calculations based on the realistic tapered probe geometry. The asymmetry distribution is due to the simultaneous presence of horizontal and vertical electric fields in the near field.