Period measurement of a periodic structure by using a heterodyne grating interferometer

This paper proposes an alternative method for grating period measurement based on heterodyne grating interferometry. The optical configurations for measuring the period of reflection/transmission gratings were demonstrated, and four commercially available gratings were used to evaluate the effective...

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Published inApplied optics. Optical technology and biomedical optics Vol. 63; no. 15; p. 4211
Main Authors Hsu, Cheng-Chih, Tsai, Chen-Ming, Ye, Chen-Yu, Chen, Pei-Ling, Lee, Tzu-Ti, Dai, Zhi-Xuan
Format Journal Article
LanguageEnglish
Published United States 20.05.2024
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Summary:This paper proposes an alternative method for grating period measurement based on heterodyne grating interferometry. The optical configurations for measuring the period of reflection/transmission gratings were demonstrated, and four commercially available gratings were used to evaluate the effectiveness of the proposed method. Based on the phase-lock technique, the grating period could be obtained immediately through the phase wrapped/unwrapped process. Under precise measurement conditions, the grating period measurement error of the proposed method was better than 1 nm, and the grating period difference between product specifications was less than 1%. In addition, the measurement results of the proposed method also exhibited high similarity with optical microscopy measurements.
ISSN:2155-3165
DOI:10.1364/AO.521993