Hideki MARUYAMA,^1,* Teruki MITSUYAMA,^3,* Masato OHMI² and Masamitsu HARUNA²

¹Research & Development Laboratory, Kyushu Matsushita Electric Co.,Ltd., 1-62, 4-Chome, Minoshima, Hakata-Ku, Fukuoka, 812-8531 Japan, ²School of Allied Health Sciences, Faculty of Medicine, Osaka University, 1-7, Yamada-Oka, Suita, Osaka, 565-0871 Japan, ³Course of Electronic Engineering, Graduate School of Engineering, Osaka University,2-1, Yamada-Oka, Suita, Osaka, 565-0871 Japan

(Received April 14, 2000; Accepted May 29, 2000)

Low coherence interferometry can provide simultaneous measurement of refractive index n and thickness t of a transparent plate, as reported recently by some research groups. Precise measurement of n and t is impossible unless chromatic dispersion of index is taken into account. We then proposed and demonstrated a unique technique for simultaneous measurement of phase index n_p, group index n_g and thickness t using a special sample holder. This paper describes a novel technique for simultaneous measurement of n_p, n_g and t using an approximate expression of the chromatic dispersion in terms of n_p. The approximate expression of chromatic dispersion does not require use of the special sample holder, and n_p, n_g and t are determined from two measurable quantities with an accuracy of 0.3% or less, for the sample thickness was around 1 mm. In addition, it is possible to shorten the measurement time compared with the above method.

Key words : low coherence light source, interferometry, simultaneous measurement of index and thickness, chromatic dispersion of index, opto-electronics

maru@mdr.kme.mei.co.jp