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**Correlation of errors in inverse problems of optical coatings monitoring.**
*(English)*
Zbl 1484.78007

Summary: On-line optical monitoring of multilayer coating production requires solving inverse identification problems of determining the thicknesses of coating layers. Regardless of the algorithm used to solve inverse problems, the errors in the thicknesses of the deposited layers are correlated by the monitoring procedure. Studying the correlation of thickness errors is important for the production of the most complex optical coatings. We develop a general geometric approach to study this correlation. It is based on a statistical analysis of large numbers of error vectors obtained during computational experiments on optical coating production. The application of the proposed approach is demonstrated using computational manufacturing experiments on the production of a 50-layer filter with four different monitoring strategies. A special coefficient is introduced to evaluate the strength of the error correlation effect. The results obtained confirm that the introduced parameter can be used as a measure of the strength of the correlation effect in practical applications.

### MSC:

78A46 | Inverse problems (including inverse scattering) in optics and electromagnetic theory |

93B30 | System identification |

### Keywords:

inverse problems; electrodynamics; optical coatings; optical monitoring; identification problems; error correlation
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\textit{I. V. Kochikov} et al., J. Inverse Ill-Posed Probl. 28, No. 6, 915--921 (2020; Zbl 1484.78007)

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