Abstract

The flexibility of a holographic optical element means great potential use. Developed as a part of an optical system, its main advantage stems from its functions and combinations of them that other components cannot provide. All of these are supported by the optically reconstructed waves. Conical waves have been established as a solution of the wave equation.¹ These waves focus in lines that are not parallel to the hologram plane, and they do not exhibit speckle. Several of these foci constitute a 3-D light distribution which can be used to determine the position and the orientation of homogeneous object surfaces. The inclination of the line foci converts longitudinal displacements of the surface into lateral image displacements on a position sensitive optoelectronic detector (triangulation principle). The proposed special illumination scheme allows one to build small combined illumination and detection units of large aperture. The image is converted in real time, e.g., with a CCD array. Several isolated spots result, whose coordinates determine longitudinal position and orientation of the object surface.

© 1991 Optical Society of America