Effect of an annular pupil filter on differential confocal microscopy.
Combining differential confocal microscopy and an annular pupil filter, we obtained the normalized axial intensity distribution curve of an optical system. We used the sharp slopes of the axial response curve of the optical system to measure the surface profile of a reflection grating. Experimental results prove that this method can extend the axial dynamic range and improve the transverse resolution of three-dimensional profilometry by sacrificing axial resolution.
Liu
L
L
Laboratory for High Intensity Optics, Shanghai Institute of Optics and Fine Mechanics, The Chinese Academy of Science, Shanghai 201800, China.
Deng
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X
Yang
L
L
Wang
G
G
Xu
Z
Z