Methods Of Synthesis And Testing Of Metrological Holographic Gratings

Abstract

Discussed in the paper are new methods of synthesis and testing of high-precision metrological holographic grating used as scales for the measurement of linear displacement, Application of two -frequency phase modulation has permitted a substantially better accuracy of manufacture and testing of holographic gratings. INuO,DU¢TIONSnowballing progress of steady -of-the -art technologies issues the challenge of precision measurement, specifically in the measurement of linear displacement. Widely used universally are diffraction grating linear transducers. These gratings are manufactured by lithographic technique using master gratings made with the help of special ruling engines. A ruling engine is a package of sophisticated optoelectronic and mechanical hardware which must operate continuously, with unfailing reliability and accuracy, for tens of hours as long as the original-ruling cycle lasts. Unavoidably, such a long process involves fluctuations of parameters of the operating environment and wear of tools making grooves on the surface of the substrate.All this sets limitations on the accuracy of the finished original and consequent., ly the replicas. By now ruling engines virtually exhausted their accuracy capabilities, and it is hardly possible to anticipate a new generation of ruled gratings that would meet the strict requirements on the first class accuracy linear transducers. SP/E Vol. 1183 Holography '89 / 653Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/16/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx