Modeling Alignment Experiment Errors for Improved Computer-Aided Alignment

Contrary to the academic interests of other existing studies elsewhere, this study deals with how thealignment algorithms such as sensitivity or Differential Wavefront Sampling (DWS) can be better usedunder effects from field, compensator positioning and environmental errors unavoidable from the shop-flooralignment work. First, the influences of aforementioned errors to the alignment state estimation wasinvestigated with the algorithms. The environmental error was then found to be the dominant factorinfluencing the alignment state prediction accuracy. Having understood such relationship between thedistorted system wavefront caused by the error sources and the alignment state prediction, we used it forsimulated and experimental alignment runs for Infrared Optical System (IROS). The difference betweentrial alignment runs and experiment was quite close, independent of alignment methods; 6 nm rms forsensitivity method and 13 nm rms for DWS. This demonstrates the practical usefulness and importanceof the prior error analysis using the alignment algorithms before the actual alignment runs begin. Theerror analysis methodology, its application to the actual alignment of IROS and their results are describedtogether with their implications. KCI Citation Count: 4