
Proceedings Paper
Freeform metrology based on phase retrieval and computer-generated hologramFormat | Member Price | Non-Member Price |
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Paper Abstract
Recently, interferometric null-testing with computer-generated hologram has been proposed as a non-contact and high
precision solution to the freeform optics metrology. However, the interferometry solution owns some typical
disadvantages such as the strong sensitivity to the table vibrations or temperature fluctuations, which hinders its usage
outside the strictly controlled laboratory conditions. Phase retrieval presents a viable alternative to interferometry for
measuring wavefront and can provide a more compact, less expensive, and more stable experimental setup. In this work,
we propose a novel solution to freeform metrology based on phase retrieval and computer-generated hologram (CGH).
The CGH is designed according to the ray tracing method, so as to compensate the aspheric aberration related to the
freeform element. With careful alignment of the CGH and the freeform element in the testing system, several defocused
intensity images can be captured for phase retrieval. In this paper the experimental results related to a freeform surface
with 18×18mm2 rectangular aperture (its peak-to-valley aspherity equals to 193um) are reported, meanwhile, we also
have compared them with the measurement results given by the interferometry solution, so as to evaluate the validity of
our solution.
Paper Details
Date Published: 5 November 2014
PDF: 8 pages
Proc. SPIE 9272, Optical Design and Testing VI, 92720E (5 November 2014); doi: 10.1117/12.2073227
Published in SPIE Proceedings Vol. 9272:
Optical Design and Testing VI
Yongtian Wang; Chunlei Du; José Sasián; Kimio Tatsuno, Editor(s)
PDF: 8 pages
Proc. SPIE 9272, Optical Design and Testing VI, 92720E (5 November 2014); doi: 10.1117/12.2073227
Show Author Affiliations
Fa Zeng, Tsinghua Univ. (China)
Qiaofeng Tan, Tsinghua Univ. (China)
Yi Liu, China Precision Engineering Institute (China)
Qiaofeng Tan, Tsinghua Univ. (China)
Yi Liu, China Precision Engineering Institute (China)
Huarong Gu, Tsinghua Univ. (China)
Zhehai Zhou, Beijing Information Science and Technology Univ. (China)
Guofan Jin, Tsinghua Univ. (China)
Zhehai Zhou, Beijing Information Science and Technology Univ. (China)
Guofan Jin, Tsinghua Univ. (China)
Published in SPIE Proceedings Vol. 9272:
Optical Design and Testing VI
Yongtian Wang; Chunlei Du; José Sasián; Kimio Tatsuno, Editor(s)
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