[OPTICAL REVIEW Vol. 9, No. 3 (2002) 112-121]

Profilometry of Sloped Plane Surfaces by Wavelength Scanning Interferometry

Akihiro YAMAMOTO and Ichirou YAMAGUCHI

Optical Engineering Laboratory, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198 Japan

(Received January 17, 2002; Accepted March 18, 2002)

The feasibility of surface shape measurement by wavelength scanning interferometry was investigated by applying it to plane surfaces with various slope angles. We derived the surface height from the peak position of the Fourier transform of the interference signals arising from wavelength scanning of a dye laser at each pixel of a CCD camera, and succeeded in measuring both diffusely reflecting surfaces and machine-milled ones having slope angles up to 45°. Study of the influence of the slope angle on the standard deviations of the measured height showed that the standard deviation increases with increase of the angle of both surfaces. The increase in diffusely reflecting surfaces could be explained in terms of speckle decorrelation caused by wavelength change.

Key words: profilometry, wavelength scanning interferometry, image processing