[OPTICAL REVIEW Vol. 8, No. 2 (2001) 90-94]

Diameter and Refractive Index of a Cylindrical Thread Determined byScattered Light Pattern

Yoshio NISHIYAMA,1 Susumu KURITA,2 Ikuo YAMAMOTO,2 Yasuhiro ISHIZUKA,1 Toru WATANABE,3 Daisuke KOBAYASHI,3 Ken-ichi ODANAKA3 and Yuka HYOGO3

1Science Education Division, Faculty of Education and Human Sciences, 2Department of Physics, Faculty of Engineering,3Department of Physics, Faculty of Education, Yokohama National University, Yokohama, 240-8501 Japan

(Received October 14, 2000; Accepted December 22, 2000)

We have devised a method of determining the optimal value of both the refractive index n and the diameter D of a transparent cylinder by the scattering intensity pattern over a wide range of scattering angle. We have shown that the method is stable to small variations of data for the sample with D≤10λ (wavelength) and could specifically determine the parameters of a spider's thread as n=1.520 (− 0.033, + 0.033), D=0.564 (− 0.009, + 0.011)μm for λ=632.8 nm.

Key words : scattering measurements, index measurements, fiber measurements, pattern recognition and feature extraction