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196 results on '"Wu, Yulie"'

52. Sphere-to-sphere diffraction propagation method for a phase-retrieval algorithm in the measurement of optical surfaces

Author

Wu, Yulie, Ding, Linyan, and Hu, Xiaojun

Subjects
Algorithms -- Methods, Algorithms -- Usage, Optical measurements -- Methods, Optics -- Research, Optics -- Methods, Algorithm, Astronomy, Physics
Abstract

We present an improved phase-retrieval algorithm that is based on the Sziklas and Siegman coordinate transformation (SSCT) and applied to optical surface testing. With the SSCT, a spherical-wave diffraction problem can be transformed into a plane-wave diffraction problem, and the fast Fourier transform can be applied directly in propagation computations. Compared with conventional diffraction propagation methods, the proposed method is simple and relatively fast, and the computation efficiency for the phase-retrieval algorithm can be increased to a certain degree. Analysis and simulation were performed for this method, and simulation results exhibit correct diffraction computation and good phase-retrieval capability. A practical 200 mm diameter, f/5 spherical surface was tested; testing results showed good agreement with that of a ZYGO interferometer, which confirmed the feasibility and accuracy of the proposed method. OCIS codes: 100.5070, 120.5050, 120.3940.

Published
2010

56. Subsurface damage distribution in the lapping process

Author

Wang, Zhuo, Wu, Yulie, Dai, Yifan, and Li, Shengyi

Subjects
Grinding and polishing -- Research, Machining -- Research, Materials research, Astronomy, Physics
Abstract

To systematically investigate the influence of lapping parameters on subsurface damage (SSD) depth and characterize the damage feature comprehensively, maximum depth and distribution of SSD generated in the optical lapping process were measured with the magnetorheological finishing wedge technique. Then, an interaction of adjacent indentations was applied to interpret the generation of maximum depth of SSD. Eventually, the lapping procedure based on the influence of lapping parameters on the material removal rate and SSD depth was proposed to improve the lapping efficiency. OCIS codes: 160.2750, 220.4610, 350.1820.

Published
2008

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