A novel algorithm for high sensitivity in measuring surface variation based on volume holography

A novel design for the precise measurement of surface variation based on volume holography is proposed. The volume hologram is a spatial filler, which records the index grating corresponding to the interference frniges by a plane wave and a divergent spherical wave. In the measuring process, a point source attached to a probe is used to read the hologram. A precise measurement can be achieved because the horizontal displacement of the point source is very sensitive to the hologram. This sensitivity is higher than that of a holographic confocal microscopy based on the longitudinal displacement. (C) 2002 Wiley Periodicals, Inc.