Retro-Reflection of Round Fibers

Abstract

Optical properties of round fibers are studied analytically and experimentally. By means of geometric optics and luminosity, the surface reflection, internal surface reflection, and transmission light of fibers are analyzed with a nearly ideal fiber, a glass rod. The angle and intensity of light scattered from a round glass rod is measured. The distribution scope of the surface reflection is 360°, and the distribution of the intensity takes the shape of an M. The scope of transmission is greater than 180°, the distribution shape of the intensity is a bell, and the maximum intensity is in the same direction as the incidence light. The distribution of internal surface reflection is narrow, the distribution of the intensity has a U shape, and the intensity reaches the maximum at the borderline. The scope of internal surface reflection decreases with the increasing refractive index of the fibers. When the index is 2, the direction of the internal surface reflection points to the light source, and it is not related to the incident angle of light.