Laser Technology, Volume. 48, Issue 6, 906(2024)

Measurement method for surface topography based on quadriwave lateral shearing interferometry

DONG Zhengqiong1, HUANG Xianwen1, XU Ren1, ZHU Renlong1, ZHOU Xiangdong1, and NIE Lei1,2、*
Author Affiliations
  • 1Key Laboratory of Modern Manufacture Quality Engineering, School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China
  • 2Xiangyang Industrial Institute of Hubei University of Technonogy, Xiangyang 441100, China
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    In order to solve the problems of high processing difficulty and limited spectral application range of specific spectra device in traditional quadriwave lateral shearing interferometry system, dividing incident light beam into four beams of lateral shearing coherent wavelets was proposed by using a spatial light modulator instead of a spectro grating. The diffraction efficiency of wavelets was adjusted flexibly by adjusting the refractive index of grating to adapt to the illumination light source, and the optical path difference distribution reflecting the height information and refractive index of the sample was reconstructed according to the interference effect between two wavelets, so as to realize accurate measurement of surface topography in a wide spectral and large dimensions range. In this study, the effect of incident light wavelength on the reconstruction accuracy of optical path difference was investigated by combining the Fourier transform method, and a wide spectrum quadriwave lateral shearing interferometry system from the visible to near infrared was built using a spatial light modulator. The results show that the system measured the etching depth of a standard quartz sample at 209.39 nm±1.72 nm, which is basically consistent with its nominal value of 210.83 nm±2.39 nm and the measurement value of 212.92 nm±1.35 nm by white light interferometer, which verifies the effectiveness of the surface topography measurement method proposed. This study can provide a theoretical reference for the extended application of quadriwave lateral shearing interferometry in the field of surface topography measurement.

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    DONG Zhengqiong, HUANG Xianwen, XU Ren, ZHU Renlong, ZHOU Xiangdong, NIE Lei. Measurement method for surface topography based on quadriwave lateral shearing interferometry[J]. Laser Technology, 2024, 48(6): 906

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    Paper Information

    Category:

    Received: Sep. 11, 2023

    Accepted: Feb. 13, 2025

    Published Online: Feb. 13, 2025

    The Author Email: NIE Lei (leinie@hbut.edu.cn)

    DOI:10.7510/jgjs.issn.1001-3806.2024.06.017

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