Stitching interferometry using alternating calibration of positioning and systematic errors

Area of Science:

• Optical Engineering
• Metrology
• Surface Metrology

Background:

• Stitching interferometry is crucial for high-precision, non-contact measurement of large optical surfaces.
• Subaperture positioning and systematic errors significantly reduce the accuracy of full-aperture surface reconstruction.

Purpose of the Study:

• To develop a novel stitching interferometry method to accurately decouple and calibrate positioning and systematic errors.
• To enhance the precision of full-aperture surface reconstruction in stitching interferometry.

Main Methods:

• Introduced Stitching Interferometry with Alternating Calibration (SIAC) to decouple positioning and systematic errors.
• Developed an iterative weighted phase stitching model with vertical projection for positioning error calibration.
• Utilized single subaperture rotation measurements and global fitting for reference error correction.

Main Results:

• Numerical simulations confirmed the efficacy of SIAC in calibrating positioning and systematic errors.
• Experimental measurements on a plane mirror and gullwing aspheres validated the method's accuracy and practicality.
• Achieved accurate stitched full-aperture phase distributions and positive cross-testing outcomes.

Conclusions:

• SIAC effectively calibrates positioning and systematic errors, enabling accurate phase stitching.
• The developed method significantly enhances the precision and practicality of stitching interferometry for optical surface measurements.