A highly phase-sensitive heterodyne polariscope for the full-field measurement of twisted-nematic liquid crystal

Tsung Chih Yu; Yu Lung Lo

doi:10.1109/LPT.2008.2004677

A highly phase-sensitive heterodyne polariscope for the full-field measurement of twisted-nematic liquid crystal

Tsung Chih Yu, Yu Lung Lo

Department of Mechanical Engineering

Research output: Contribution to journal › Article › peer-review

6 Citations (Scopus)

Abstract

This study proposes a highly phase-sensitive imaging polariscope with a common-path heterodyne configuration for the mapping of spatially distributed cell gap of a twisted-nematic liquid crystal (TNLC). The polariscope adopts an electrooptic modulator incorporated with a quarter-wave plate to modulate the linear polarized light. By applying an integrating-bucket method, the two-dimensional (2-D) phase distribution of the detected heterodyne signal is extracted for the inverse calculation of the TNLC cell thickness. The proposing system has no need to remove or to rotate any optical elements in the measuring process and makes it possible to perform high-speed 2-D mapping. The dynamic range of retardation is around 0.7 μm without ambiguity in the proposing method. By using a standard 8-bit gray level charged-coupled device (CCD), the experimental result shows that the standard deviation of 1.8 nm in the 2-D measurement of cell thickness has been obtained. The retardation resolution of 0.5 nm of the proposed method is also achieved and is better than that of the Stokes parameters determination method with high gray level CCD.

Original language	English
Pages (from-to)	1778-1780
Number of pages	3
Journal	IEEE Photonics Technology Letters
Volume	20
Issue number	21
DOIs	https://doi.org/10.1109/LPT.2008.2004677
Publication status	Published - 2008

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Atomic and Molecular Physics, and Optics
Electrical and Electronic Engineering

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10.1109/LPT.2008.2004677

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title = "A highly phase-sensitive heterodyne polariscope for the full-field measurement of twisted-nematic liquid crystal",

abstract = "This study proposes a highly phase-sensitive imaging polariscope with a common-path heterodyne configuration for the mapping of spatially distributed cell gap of a twisted-nematic liquid crystal (TNLC). The polariscope adopts an electrooptic modulator incorporated with a quarter-wave plate to modulate the linear polarized light. By applying an integrating-bucket method, the two-dimensional (2-D) phase distribution of the detected heterodyne signal is extracted for the inverse calculation of the TNLC cell thickness. The proposing system has no need to remove or to rotate any optical elements in the measuring process and makes it possible to perform high-speed 2-D mapping. The dynamic range of retardation is around 0.7 μm without ambiguity in the proposing method. By using a standard 8-bit gray level charged-coupled device (CCD), the experimental result shows that the standard deviation of 1.8 nm in the 2-D measurement of cell thickness has been obtained. The retardation resolution of 0.5 nm of the proposed method is also achieved and is better than that of the Stokes parameters determination method with high gray level CCD.",

author = "Yu, {Tsung Chih} and Lo, {Yu Lung}",

note = "Funding Information: Manuscript received July 17, 2008. First published August 22, 2008; current version published October 15, 2008. This work was supported by the National Science Council, Taiwan, under Grant NSC96-2628-E-006-005-MY3. The authors are with the Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (e-mail: loyl@mail.ncku.edu.tw). Color versions of one or more of the figures in this letter are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/LPT.2008.2004677",

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AU - Yu, Tsung Chih

AU - Lo, Yu Lung

N1 - Funding Information: Manuscript received July 17, 2008. First published August 22, 2008; current version published October 15, 2008. This work was supported by the National Science Council, Taiwan, under Grant NSC96-2628-E-006-005-MY3. The authors are with the Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (e-mail: loyl@mail.ncku.edu.tw). Color versions of one or more of the figures in this letter are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/LPT.2008.2004677

PY - 2008

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N2 - This study proposes a highly phase-sensitive imaging polariscope with a common-path heterodyne configuration for the mapping of spatially distributed cell gap of a twisted-nematic liquid crystal (TNLC). The polariscope adopts an electrooptic modulator incorporated with a quarter-wave plate to modulate the linear polarized light. By applying an integrating-bucket method, the two-dimensional (2-D) phase distribution of the detected heterodyne signal is extracted for the inverse calculation of the TNLC cell thickness. The proposing system has no need to remove or to rotate any optical elements in the measuring process and makes it possible to perform high-speed 2-D mapping. The dynamic range of retardation is around 0.7 μm without ambiguity in the proposing method. By using a standard 8-bit gray level charged-coupled device (CCD), the experimental result shows that the standard deviation of 1.8 nm in the 2-D measurement of cell thickness has been obtained. The retardation resolution of 0.5 nm of the proposed method is also achieved and is better than that of the Stokes parameters determination method with high gray level CCD.

AB - This study proposes a highly phase-sensitive imaging polariscope with a common-path heterodyne configuration for the mapping of spatially distributed cell gap of a twisted-nematic liquid crystal (TNLC). The polariscope adopts an electrooptic modulator incorporated with a quarter-wave plate to modulate the linear polarized light. By applying an integrating-bucket method, the two-dimensional (2-D) phase distribution of the detected heterodyne signal is extracted for the inverse calculation of the TNLC cell thickness. The proposing system has no need to remove or to rotate any optical elements in the measuring process and makes it possible to perform high-speed 2-D mapping. The dynamic range of retardation is around 0.7 μm without ambiguity in the proposing method. By using a standard 8-bit gray level charged-coupled device (CCD), the experimental result shows that the standard deviation of 1.8 nm in the 2-D measurement of cell thickness has been obtained. The retardation resolution of 0.5 nm of the proposed method is also achieved and is better than that of the Stokes parameters determination method with high gray level CCD.

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A highly phase-sensitive heterodyne polariscope for the full-field measurement of twisted-nematic liquid crystal

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