Three-dimensional location and measurement by coherent optical methods

The availability of lasers with high coherence and stability suggests ways of recording spatial relationships and of making positional measurements with greater precision. Examples are quoted of optical measurements made with coherent light in real-time experiments, and the extension to the photographic recording of holograms for measurement is shown. Measurement via holography has been carried out for transilluminated, three-dimensional arrays of spheres, moving and measurable in three dimensions, and of solid three-dimensional bodies, also moving and measurable in three dimensions. Current work is introduced by means of an example of a photofabricated optical element capable of identifying positions in a three-dimensional space.