Imperfections of Scalar Approximation in Calibration of Computer-Generated Holograms for Optical Surface Measurements

Autor: Yingying Bai, Zhiyu Zhang, Ruoqiu Wang, Tianbao Chen, Xu Wang, Xuejun Zhang
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Applied Sciences, Vol 11, Iss 15, p 6897 (2021)
Druh dokumentu: article
ISSN: 2076-3417
DOI: 10.3390/app11156897
Popis: Computer-generated hologram (CGH) null correctors are used as accuracy standards for interferometric measurements of optical surfaces and optical systems. Diffractive optics calibrators (DOCs) have been developed to evaluate the phase tolerance of CGHs based on scalar approximation by measuring variations in duty cycle and etching depth. However, if the grating period of a CGH < 5λ, the scalar approximation is not accurate for phase analysis and reconstruction. In this study, the measurement errors of DOCs with small-period CGHs were investigated and experimentally verified. Results show that the imperfections of scalar approximation in CGHs cannot be ignored and the development of rigorous evaluation methods to improve the measurement accuracy of CGHs is of great practical significance.
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