Analysis of a quasi-periodical structure through its autocorrelation function

The method of analysis and reconstruction of the structure for a 1-D nonregular grating composed of N identical apertures is discussed. The transmittance function of the grating is expressed as the sum of transmittance functions of pairs of the apertures, and the classes of these pairs are determined through their separation. Applying the autocorrelation technique to the function of intensity distribution in the far field of such a grating's transmittance, it is possible to determine grating autocorrelation function. This function contains complete information concerning the actual structure of the grating itself, i.e., classes of the pairs of the apertures and their populations. With such information, it is possible to reconstruct the structure of the object. (C) 1996 Society of Photo-Optical Instrumentation Engineers.