Development of a polarization-preserving optical-fiber probe for near-field scanning optical microscopy and the influences of bending and squeezing on the polarization properties

Abstract

We have characterized the optical properties of a polarization-preserving near-field scanning optical microscopy (NSOM) optical fiber probe, and evaluated the influence of probe fabrication processes, such as melting-pulling and bending, on those properties. We found that the extinction ratio always decreases on the linearly polarized light parallel to the slow axis, and that the decrease is independent of the direction in which the probe is bent. The most probable cause of the low extinction ratio is the isotropic compression stress occurring when the fiber is squeezed; such stress cancels out the tensile stress applied to the core by stress applicators. Using the polarization-preserving NSOM probe, we observed the optical properties of the propagation light within a polymeric optical waveguide in guide-collection mode, and investigated those properties with various polarization conditions of incident light and probe collection.