Interferometric determination of the optical properties of fibres with irregular transverse sections (Ramie)

Abstract

SUMMARY The thickness of fibres and their irregularity were determined from the forward scattering of a He‐Ne laser beam. Two methods have been used for the measurement of refractive indices and birefringence of Ramie fibres. The first of these methods is the application of multiple‐beam Fizeau fringes in transmission and at reflection. The second is the use of the double refracting interference microscope designed and developed by Pluta. In each method, refractive index values have been determined using two different analyses of the interference pattern. To overcome the difficulty of the irregular transverse section of Ramie fibres, the area enclosed under the fringe shift is considered as representing the path difference integrated across the fibre.

Transmission Mueller-matrix characterization of transparent ramie films

“…16 The results of our work agree well with the corresponding birefringence Δn = n | | -n ⊥ = 0.070. Other studies using interferometric methods at a wavelength of 546.1 nm reported by Hamza et al 17 gave birefringence values between 0.047 and 0.055, whereas Sokkar and Shahin 18 reported a higher value of 0.067. As expected, a thicker film produces larger retardation orders leading to more frequent variations between −π and +π.…”