• Chinese Journal of Lasers
  • Vol. 42, Issue 9, 908006 (2015)
Zeng Yanan*, Lei Hai, Chang Xinyu, Hu Xiaodong, and Hu Xiaotang
DOI: 10.3788/cjl201542.0908006 Cite this Article Set citation alerts
Zeng Yanan, Lei Hai, Chang Xinyu, Hu Xiaodong, Hu Xiaotang. Phase Retrieval with One Interferogram by Reflecting Off-Axis Microscopic Interferometry[J]. Chinese Journal of Lasers, 2015, 42(9): 908006 Copy Citation Text show less

Abstract

A technique called off-axis microscopic interferometry is developed to measure the surface profile of microstructures. This technique involves the use of a modified Mach-Zehnder microscopic interferometer with a tilted reference wave. The technique uses a CCD camera to record the off-axis microscopic interferogram and performs filtering in the Fourier plane via the Fourier transform method for phase retrieval. In contrast to classical microscopic interferometry, the carrier frequency of the off-axis microscopic interferogram is sufficiently high to facilitate acquisition of the phase from only one interferogram. As a result, measurements using this technique are vibration-immune and efficient. The experimental results obtained for a step height standard as well as a microhole array are consistent with measurements taken using a stylus profilometer. Further, the results of a comparative experiment conducted using a Mirau interferometric microscope show that the carrier frequency added to the classical microscopic interferogram cannot be as high as that of off-axis microscopic interferogram. Therefore, it will lead to incorrect phase retrieval with one interferogram.
Zeng Yanan, Lei Hai, Chang Xinyu, Hu Xiaodong, Hu Xiaotang. Phase Retrieval with One Interferogram by Reflecting Off-Axis Microscopic Interferometry[J]. Chinese Journal of Lasers, 2015, 42(9): 908006
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