Abstract

Microscope projection fringes are formed by intersecting two expanded laser beams. Planes of interference exist within the entire interaction volume, the spacing being dependent on their intersecting angle. Inserting an object into this volume results in projection fringes on its surface which represent cross sections through the surface. The fringe pattern is then analyzed digitally to yield a contour map of the surface. A great advantage of this system is the case with which the resolution may be varied. Results are presented for two different surfaces. One surface is a block of aluminum into which submillimeter grooves have been machined. The other surface is an iron alloy into which grooves have been burned with a pulsed CO₂ laser. Results for this surface are shown at three different (microns) resolutions.

© 1986 Optical Society of America