Development of an Automated Phase-Shifting Interferometer Using a Homemade Liquid-Crystal Phase Shifter

In this paper, an automatic phase-shifting interferometer has been developed using a homemade liquid-crystal phase shifter, which demonstrates a low-cost, fully automated technical solution for measuring the phase information of optical waves in devices. Conventional phase-shifting interferometers u...

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Main Authors: Zhenghao Song, Lin Xu, Jing Wang, Xitong Liang, Jun Dai
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Photonics
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Online Access:https://www.mdpi.com/2304-6732/12/7/722
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author Zhenghao Song
Lin Xu
Jing Wang
Xitong Liang
Jun Dai
author_facet Zhenghao Song
Lin Xu
Jing Wang
Xitong Liang
Jun Dai
author_sort Zhenghao Song
collection DOAJ
description In this paper, an automatic phase-shifting interferometer has been developed using a homemade liquid-crystal phase shifter, which demonstrates a low-cost, fully automated technical solution for measuring the phase information of optical waves in devices. Conventional phase-shifting interferometers usually rely on PZT piezoelectric phase shifters, which are complex, require additional half-inverse and half-transparent optics to build the optical path, and are expensive. To overcome these limitations, we used a laboratory-made liquid-crystal waveplate as a phase shifter and integrated it into a Mach–Zehnder phase-shifting interferometer. The system is controlled by an STM32 microcontroller and self-developed measurement software, and it utilizes a four-step phase-shift interferometry algorithm and the CPULSI phase-unwrapping algorithm to achieve automatic phase measurements. Phase test experiments using a standard plano-convex lens and a homemade liquid-crystal grating as test objects demonstrate the feasibility and accuracy of the device by the fact that the measured focal lengths are in good agreement with the nominal values, and the phase distributions of the gratings are also in good agreement with the predefined values. This study validates the potential of liquid-crystal-based phase shifters for low-cost, fully automated optical phase measurements, providing a simpler and cheaper alternative to conventional methods.
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spelling doaj-art-e1fbfc067cd34d4e997c92ff95b49a772025-08-20T03:08:10ZengMDPI AGPhotonics2304-67322025-07-0112772210.3390/photonics12070722Development of an Automated Phase-Shifting Interferometer Using a Homemade Liquid-Crystal Phase ShifterZhenghao Song0Lin Xu1Jing Wang2Xitong Liang3Jun Dai4School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, ChinaSchool of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, ChinaSchool of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, ChinaSchool of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, ChinaSchool of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, ChinaIn this paper, an automatic phase-shifting interferometer has been developed using a homemade liquid-crystal phase shifter, which demonstrates a low-cost, fully automated technical solution for measuring the phase information of optical waves in devices. Conventional phase-shifting interferometers usually rely on PZT piezoelectric phase shifters, which are complex, require additional half-inverse and half-transparent optics to build the optical path, and are expensive. To overcome these limitations, we used a laboratory-made liquid-crystal waveplate as a phase shifter and integrated it into a Mach–Zehnder phase-shifting interferometer. The system is controlled by an STM32 microcontroller and self-developed measurement software, and it utilizes a four-step phase-shift interferometry algorithm and the CPULSI phase-unwrapping algorithm to achieve automatic phase measurements. Phase test experiments using a standard plano-convex lens and a homemade liquid-crystal grating as test objects demonstrate the feasibility and accuracy of the device by the fact that the measured focal lengths are in good agreement with the nominal values, and the phase distributions of the gratings are also in good agreement with the predefined values. This study validates the potential of liquid-crystal-based phase shifters for low-cost, fully automated optical phase measurements, providing a simpler and cheaper alternative to conventional methods.https://www.mdpi.com/2304-6732/12/7/722phase-shifting interferometerliquid-crystal phase shifterautomated optical metrologyphase-unwrapping algorithm
spellingShingle Zhenghao Song
Lin Xu
Jing Wang
Xitong Liang
Jun Dai
Development of an Automated Phase-Shifting Interferometer Using a Homemade Liquid-Crystal Phase Shifter
Photonics
phase-shifting interferometer
liquid-crystal phase shifter
automated optical metrology
phase-unwrapping algorithm
title Development of an Automated Phase-Shifting Interferometer Using a Homemade Liquid-Crystal Phase Shifter
title_full Development of an Automated Phase-Shifting Interferometer Using a Homemade Liquid-Crystal Phase Shifter
title_fullStr Development of an Automated Phase-Shifting Interferometer Using a Homemade Liquid-Crystal Phase Shifter
title_full_unstemmed Development of an Automated Phase-Shifting Interferometer Using a Homemade Liquid-Crystal Phase Shifter
title_short Development of an Automated Phase-Shifting Interferometer Using a Homemade Liquid-Crystal Phase Shifter
title_sort development of an automated phase shifting interferometer using a homemade liquid crystal phase shifter
topic phase-shifting interferometer
liquid-crystal phase shifter
automated optical metrology
phase-unwrapping algorithm
url https://www.mdpi.com/2304-6732/12/7/722
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AT jingwang developmentofanautomatedphaseshiftinginterferometerusingahomemadeliquidcrystalphaseshifter
AT xitongliang developmentofanautomatedphaseshiftinginterferometerusingahomemadeliquidcrystalphaseshifter
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