Mixed stitching interferometry with correction from one-dimensional profile measurements for high-precision X-ray mirrors.

Abstract

This work presents a mixed stitching interferometry method with correction from one-dimensional profile measurements. This method can correct the error of stitching angles among different subapertures using the relatively accurate one-dimensional profiles of the mirror, e.g., provided by the contact profilometer. The measurement accuracy is simulated and analyzed. The repeatability error is decreased by averaging multiple measurements of the one-dimensional profile and using multiple profiles at different measurement positions. Finally, the measurement result of an elliptical mirror is presented and compared with the global algorithm-based stitching, and the error of the original profiles is reduced to one-third. This result shows that this method can effectively suppress the accumulation of stitching angle errors in classic global algorithm-based stitching. The accuracy of this method can be further improved by using high-precision one-dimensional profile measurements such as the nanometer optical component measuring machine (NOM).