Optical modeling of light scattering for refractive-index detection of liquids in a microcapillary with low-coherence rainbow diffractometry

摘要

This work provides a numerical analysis of elastic light scattering by a fused silica capillary for noninvasive sensing of the refractive index for the purposes of capillary electrophoresis (CE). A capillary containing the sample liquid is illuminated by a beam of light of low temporal coherence. The scattering far-field pattern is analyzed in the vicinity of multiple primary rainbows. The paper offers both explanation of the scattering mechanisms contributing to the far-field intensity pattern based on numerical simulations as well as an analysis of the sensitivity of the measurement data to changes in the refractive index.