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Proceedings Paper

A novel aspherical surface measurement system based on a randomly encoded hybrid grating wavefront sensor
Author(s): Rui Zhang; Yongying Yang; Zijian Liang
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Paper Abstract

A novel aspherical surface measurement system based on randomly encoded hybrid grating (REHG) wavefront sensor is proposed. The system utilizes a non-null testing compensation lens to partially compensate the normal aberration of aspheric surface under test, which is more general than the null testing system. Different from the conventional interferometers, the REHG wavefront sensor exhibits strong anti-vibration ability and larger dynamic range due to its common path and self-reference characteristics, and is especially suitable for the measurement of aspherical surface. In this paper, a simulation model combing quadriwave lateral shearing interferometry based on the REHG and non-null aspheric testing technology is established. The generation mechanism of retrace error is analyzed. The iterative reverse optimization (IRO) retrace error correction method based on system modeling is discussed. Computer modeling is performed based on the actual experiment configuration, and an optimization function is set with polynomial coefficients of aspherics under test as variables. Through the reverse optimization with iterative ray tracing, the retrieved wavefront of the REHG sensor in the actual experiment system and the simulated wavefront in the system model will meet the constraint condition, and the figure error of aspheric surface can be then reconstructed by the optimal solution of polynomial coefficients in the model. The feasibility and accuracy of the aspherical surface non-null measurement system based on the REHG wavefront sensor are demonstrated by the simulation experiment result with different asphericities.

Paper Details

Date Published: 3 September 2019
PDF: 7 pages
Proc. SPIE 11102, Applied Optical Metrology III, 1110209 (3 September 2019); doi: 10.1117/12.2528413
Show Author Affiliations
Rui Zhang, Zhejiang Univ. (China)
Yongying Yang, Zhejiang Univ. (China)
Zijian Liang, Zhejiang Univ. (China)

Published in SPIE Proceedings Vol. 11102:
Applied Optical Metrology III
Erik Novak; James D. Trolinger, Editor(s)

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