Abstract

Reflected (back scattered) laser light from a fluid filled Capillary Tube has been used to determine small refractive index changes in the fluid. The direction and magnitude of shift in the fringe pattern produced in the back scattered light is a function of the change in refractive index. The effect of temperature perturbation and orientation of the incident beam polarization on the sensitivity of the relative index measurement is also investigated. A linearly Polarized He-Ne Laser (P=1mW, Wavelenglh=632.8 run) is used as a beam source, an uncoated Fused Silica Capillary Tube (I.D.-530 um) is used as a Flow Cell (Cell Probed Volume=4.4x10^-7 L), and a series of low concentration glycerol-water solutions are used as sample solutions. Detection limit of the detector is 9X10^-7 change in refractive index.

© 1992 Optical Society of America