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Proceedings Paper

Design and fabrication of CGH for aspheric surface testing and its experimental comparison with null lens
Author(s): Fazhi Li; Jingli Zhao; Ruigang Li; Binzhi Zhang; Ligong Zheng; Xuejun Zhang
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Paper Abstract

Computer-generated hologram (CGH) is an effective way to compensate wavefront in null test of aspheric surfaces and freeform surfaces. Our strategies of CGH design and fabrication for optical testing are presented, and an experiment demonstrating the compensation results of CGH and null lens is also reported. In order to design complex CGH, software was developed, with which we can design a CGH including three sections: main section for compensating wavefront in null test, alignment section for adjusting the relative position between CGH and interferometer, and fiducial section for projecting fiducial marks around the optics under test. The design result is represented in GDS II format file which could drive a laser-direct-writer-machine to fabricate a photomask. Then, a 1:1 replication process is applied to duplicate the patterns from photomask to a parallel optical substrate whose surface is error better than λ/60 rms. Finally, an off-axis aspheric surface was tested with CGH and null lens respectively. The test result with CGH (0.019λ;rms) is almost the same as the result with null lens (0.020λ rms). This experiment also demonstrated that fiducial marks projected by CGH can be used to guide the alignment of the optics and measurement of its off-axis distance.

Paper Details

Date Published: 12 October 2010
PDF: 6 pages
Proc. SPIE 7656, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 765643 (12 October 2010); doi: 10.1117/12.867627
Show Author Affiliations
Fazhi Li, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Graduate Univ. of CAS (China)
Jingli Zhao, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Ruigang Li, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Binzhi Zhang, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Ligong Zheng, Changchun Institute of Optics, Fine Mechanics and Physics (China)
Xuejun Zhang, Changchun Institute of Optics, Fine Mechanics and Physics (China)


Published in SPIE Proceedings Vol. 7656:
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Yudong Zhang; Jose M. Sasian; Libin Xiang; Sandy To, Editor(s)

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