Current State Of Optical Testing

Abstract

Basic interferometry and holographic interferometry are becoming useful tools for precision measurements. The use of electronic solid state detector arrays, together with, small computers for extracting the information from the interferograms improve their applications. Computer analysis is becoming increasingly important. A lot of information can extracted from the interferograms leading to higher sensitivities and accuracies.1 New technologies to generate optical surfaces have been introduced. Progress has been made in manufacturing of metallic spherical and aspherical surfaces using diamond turning techniques, for instance. The improved production techniques will motivate the optical designer to use aspheric surfaces more frequently especially for IR applications. Using replica techniques, aspheric surfaces will be used more often in serial production of components used for the visible or near IR. In consumer products the cost of precision optics is relatively high. Using inexpensive aspheric lenses could cut the cost considerably. The application of aspherical optical surfaces could be helpfu) to reduce the number of optical elements reducing the total weight of the optical system and possibly the cost, in addition, the quality may be improved. Replication of an aspheric surface on a thin film onto a spherical glass body using photocurable la cquer is very cost effective.2 The aspheric mold as well as the resulting aspheric optical elements need to be tested. Optical contactless testing techniques using computer generated holograms can be very useful for industrial applications for micro- and macro structure analysis of aspheric surfaces.3