Possibilities of optical noncontact diagnostics of random phase objects are studied, based on measurements of transverse coherence function, scintillation index, and amplitude and phase dispersion of the field resulting from interaction with the object. The advantages of these methods are increased speed and accuracy compared with commonly used methods. Interference measurements of second- and higher-order correlation parameters of the field phase is demonstrated which can be used to find the corresponding probability density distribution function for objects with phase statistics differing from Gaussian. The sensitivity threshold of the methods is estimated to be ~0.005 μm when measuring surfaces with slight roughness.
© 1990 Optical Society of America
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