Interferogram analysis based on the data-dependent systems method for nanometrology applications.
A spatial method of wave-front phase detection from an interferogram is presented. The method uses data-dependent systems methodology, an approach that extends and improves the way the stochastic autoregressive moving average models are obtained and interpreted. Its application to interference data addresses the fundamental problem of recovering the self-coherence function commonly used to retrieve the wave-front phase. The self-coherence function is efficiently computed by means of a complex autoregressive model and is used for surface reconstruction. The method is shown to be robust and suitable for surface testing. The correspondence of the data-dependent systems methodology and its physical meaning as related to the classical interferometry are presented. The theoretical development is illustrated by experimental implementation, with the results obtained from one- and two-dimensional interferometric fringe analysis of a computer hard disk.
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