RESUMEN
Stitching interferometry is an essential technique for the non-contact, high-precision measurement of large apertures or complex optical surfaces. However, the accuracy of full-aperture surface reconstruction is significantly compromised by subaperture positioning and systematic errors. To address this challenge, this study introduces a novel stitching interferometry method utilizing alternating calibration of positioning and systematic errors (SIAC). This method calibrates one type of error while maintaining the other constant, and alternates between these processes to effectively decouple the two errors, facilitating accurate phase stitching. Within this calibration framework, an iterative weighted phase stitching model employing vertical projection for estimating overlapping areas was developed to calibrate positioning errors. Additionally, the rotation measurements of a single subaperture, in conjunction with a global fitting approach, were employed to correct reference errors. Numerical simulations have confirmed the efficacy of SIAC in calibrating these errors. Moreover, experimental measurements were performed on both a plane mirror and gullwing aspheres, with the resulting stitched full-aperture phase distributions and cross-testing outcomes affirming the method's accuracy and practicality. This research provides a novel solution for stitching interferometry, enhancing the precision of optical surface measurements.
RESUMEN
This study demonstrates a three-cavity multiplexing vibration-resistant Fizeau interferometry (TCM). The method injects a vibration-measurement pass (VMP), which utilizes three-cavity hybrid interference for the transmission of phase and vibration information, to the Fizeau phase-measurement pass (PMP). Moreover, the VMP is demultiplexed using the temporal difference of mixed fringes and synchronous phase-shifting phase extraction of difference fringe to obtain the vibration information, which is then used to calculate the measured phase combined with PMP. The feasibility and performance of the TCM are demonstrated experimentally. To the best of our knowledge, this is the first proposal of the TCM that not only solves the effect of vibration and null-fringe demodulation but also features a common path, simple testing process, and low system complexity.
RESUMEN
Aspheres have widespread applications in modern optical systems; however, the high-precision testing of the gull-wing asphere (GWA) is still challenging. In this Letter, flexible stitching interferometry (FSI) has been reported using variable-sign curvature compensation (VSCC) to realize accurate GWA testing. The method involves varying the sign and magnitude of the outgoing wavefront curvature by relative translation of VSCC to compensate for the curvatures of subapertures, and alternating optimization stitching is utilized to obtain the full-aperture absolute phase. The feasibility and performance of the proposed method are demonstrated experimentally. To our knowledge, such a stitching interferometry using VSCC is here proposed for the first time, and could contribute to general aspheric interferometry.