Interference patterns of a plane-polarized wave from a hollow glass fiber

Irradiation of a hollow glass fiber, normal to its axis, by a plane-polarized laser source produces a coaxial interference pattern with distinctive features that can be related to the cross-sectional geometry of the fiber, providing a sensitive means of non-destructive monitoring of the outer radius and the ratio of inner and outer radii. The phenomena involved in this interpretation are explained and reconstructed by use of a ray-vector approach, by which the incident wavefront is decomposed into the component interactions of reflection and refraction with the fiber to give the emergent wavefronts. A number of measurements made on some samples demonstrate the proposals.