NEW METHODS OF FABRICATION OF HIGH-APERTURE COMPUTER-SYNTHESIZED HOLOGRAMS FOR THE FORMATION OF REFERENCE WAVE FRONTS IN INTERFEROMETRY
Factors responsible for parasitic distortions of interferograms in control systems based on reference single-component high-aperture computer-synthesized holograms (CSHs), which are written on flat substrates and have a binary phase structure, are analyzed as applied to the problem of interferometric inspection of spherical and aspherical surfaces with high angular apertures. To improve the quality of such CSHs, methods, tools, and recording materials (titanium and chromium films) are used, which are suitable for the technology of direct laser recording of their diffraction structure to ensure the formation of interferograms with the minimum parasitic distortions. In particular, to reduce the variations of the interferogram contrast, it is proposed to perform modulation of the local transmission coefficient of the CSH structure by means of modulation of the duty ratio of diffraction zones. Possible applications of the thermochemical laser technology of recording on titanium and chromium films for fabrication of high-aperture holograms with a normalized orifice of f/1 and more are discussed.