Estimation of the Complex Refractive Index of Fiber Material by Measuring Scattering Intensity of the Fiber

This paper deals with an estimation method of complex refractive index (CRI) of a fiber material. The intensity distribution of scattered light from a single fiiber has been measured for a perpendicular incident beam of light. Comparison of the experimental data with the computed ones based on the model of an infinitely long circular cylinder yields the CRI of the fiber material. Two kinds of fibers such as fused silica and tungsten were studied in this paper. The CRIs estimated in this study are 1.46-0.00 · i for fused silica and 0.85–1.05·i for tungsten at the wavelength of 632.8 nm. The estimated value of CRI for the fused silica is good agreement with the earlier one.