Details of the Researcher

PHOTO

Ryo Sato
Section
Graduate School of Engineering
Job title
Assistant Professor
Degree

  • Doctor of Philosophy (Engineering) (Tohoku University)

Research History 2

  • 2021/04 - 2023/09
    Tohoku University　Graduate School of Engineering Department of Finemechanics

  • 2023/10 -
    Tohoku University

Education 2

  • Tohoku University　Graduate School of Engineering　Department of Finemechanics

    2019/04 - 2023/09

  • Tohoku University　Faculty of Engineering　Department of Mechanical and Aerospace Engineering

    2015/04 - 2019/03

Committee Memberships 5

  • The International Symposium on Optomechatronic Technology (ISOT 2026)　Program Committee

    2025/10 - Present

  • Optical Technology and Measurement for Industrial Applications Conference (OPTM2026)　Program Committee

    2025/10 - Present

  • The 8th CIRP Conference on Surface Integrity (CIRP-CSI 2026)　Publication Committee

    2025/09 - Present

  • 精密工学会　編集委員

    2025/04 - Present

  • The 20th International Conference of Precision Engineering　Organaization Committee

    2024/01 - Present

Professional Memberships 4

  • 精密工学会 知的ナノ計測専門委員会

    2025/03 - Present

  • 精密工学会 メカノフォトニクス専門委員会

    2024/03 - Present

  • JSPE Affiliate

    2024/03 - Present

  • 精密工学会

    2018/11 - Present

Research Interests 3

  • 精密位置決め

  • 光応用計測

  • 超精密計測

Research Areas 3

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Design engineering /

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Measurement engineering /

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Manufacturing and production engineering /

Awards 11

  1. アドバンスト・ベストプレゼンテーション賞

    2025/09　公益社団法人 精密工学会 2025年度精密工学会秋季大会学術講演会　非直交型2軸ロイドミラー干渉計によるスケール格子創成 —弾性曲げミラーによる不等間隔溝格子作成手法検討—

  2. Best Poster Award

    2025/05　ISMTII / ICOIM 2025　Study on confocal probe signal processing method for center of rotation and optical axis alignment

  3. Best Paper Award

    2024/12　The 9th International Conference on Nanomanufacturing　Investigation of a Signal Processing Method Based on a Dual-Detection Chromatic Confocal Probe

  4. アドバンスト・ベストプレゼンテーション賞

    2024/09　公益社団法人 精密工学会　モード同期フェムト秒レーザ共焦点プローブに関する研究-極小点追跡法を用いた合焦波長検出に関する検討-

  5. 吉澤奨励賞

    2024/03　精密工学会 メカノフォトニクス委員会　第二次高調波共焦点プローブに関する研究−角度計測に関する検討−

  6. President's Award

    2024/03　Tohoku University

  7. Best paper award

    2023/09　The 15th International Symposium on Measurement Technology and Intelligent Instruments (ISMTII2023)　Stitching interferometry method for the pitch evaluation of a large-scale variable-line-spacing diffraction grating by using a Fizeau interferometer

  8. Best Paper Award

    2022/08　The 8th International Conference on Nanomanufacturing & The 4th AET Symposium on ACSM and Digital Manufacturing(nanoMan2022 & AETS2022)　Theoretical investigation of angle measurement based on third-harmonic generation (THG) with a femtosecond laser

  9. ベストプレゼンテーション賞

    2021/09　精密工学会 2021年度精密工学会秋季大会学術講演　モード同期フェムト秒レーザ共焦点プローブに関する研究-極小点追跡法を用いた合焦波長検出に関する検討-

  10. 工学研究科長賞

    2021/03　東北大学

  11. 大学院研究奨励賞

    2021/03　公益財団法人自動車技術会

Show all ︎Show 5

Papers 40

  1. Advanced Sensing and Machine Learning Technologies for Intelligent Measurement in Smart and Precision Manufacturing Peer-reviewed

    Ryo Sato, Kuangyi Li, Masaki Michihata, Satoru Takahashi, Wei Gao

    International Journal of Automation Technology　18　(4)　545-580　2024/07/05

    Publisher: Fuji Technology Press Ltd.

    DOI： 10.20965/ijat.2024.p0545 　

    ISSN： 1881-7629

    eISSN： 1883-8022

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    This paper provides an overview of state-of-the-art sensing and machine learning technologies for intelligent measurement in smart and precision manufacturing. Length, angle, and force are identified as the fundamental quantities for production quality management based on process monitoring as well as geometrical metrology in optical lithography and mechanical machining. Advancements in length-based measurement technologies such as laser interferometers and optical encoders, as well as advancements regarding depth and thickness measurements, are presented. Various types of optical microscopes, such as evanescent field microscopes, structured illumination microscopes, and confocal microscopes, are also described. For angle-based measurement technologies, in addition to the conventional continuous-wave laser autocollimators, the newly developed Fabry–Pérot angle sensor and nonlinear optics angle sensor using an ultrashort pulse laser are presented. Finally, on-machine and in-process force sensing and machining learning techniques for dimensional and machining process monitoring are reviewed.

  2. Signal Processing and Artificial Intelligence for Dual-Detection Confocal Probes Peer-reviewed

    Ryo Sato, Xinghui Li, Andreas Fischer, Liang-Chia Chen, Chong Chen, Rintaro Shimomura, Wei Gao

    International Journal of Precision Engineering and Manufacturing　2023/06/27

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s12541-023-00842-3 　

    ISSN： 2234-7593

    eISSN： 2005-4602

  3. Confocal probe based on the second harmonic generation for measurement of linear and angular displacements Peer-reviewed

    Ryo Sato, Yuki Shimizu, Hiroki Shimizu, Hiraku Matsukuma, Wei Gao

    Optics Express　31　(7)　11982-11993　2023/03/27

    DOI： 10.1364/OE.486421 　

    eISSN： 1094-4087

  4. A new signal processing method for a differential chromatic confocal probe with a mode-locked femtosecond laser Peer-reviewed

    Ryo Sato, Chong Chen, Hiraku Matsukuma, Yuki Shimizu, Wei Gao

    Measurement Science and Technology　31　(9)　2020/09

    DOI： 10.1088/1361-6501/ab8905 　

    ISSN： 0957-0233

    eISSN： 1361-6501

  5. GUM-Based Measurement Uncertainty Analysis of a Nonlinear Optical Angle Sensor Using Artificial Neural Network Peer-reviewed

    Jiahui Lin, Zhiyang Zhang, Ryo Sato, Kuangyi Li, Yasuhiro Mizutani, Hiraku Matsukuma, Wei Gao, Robert X. Gao

    Nanomanufacturing and Metrology　8　(1)　2025/08/07

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s41871-025-00273-w 　

    ISSN： 2520-811X

    eISSN： 2520-8128

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    Abstract To address the difficulty of obtaining Guide to the Expression of Uncertainty in Measurement (GUM)-based measurement uncertainty for sensors employing artificial neural networks (ANNs) in the field of mechanical measurement, this paper proposes and demonstrates a GUM-based uncertainty evaluation method for a nonlinear optical angle sensor that uses a multilayer perceptron artificial neural network (MLP-ANN). The proposed sensor decodes the angular information of a target by inputting a measured second harmonic generation spectrum into a trained MLP-ANN to enable wide-range angle measurement. However, the measurement uncertainty of this method has not yet been evaluated, and such an analysis is essential to assess the accuracy and reliability of the sensor. This paper demonstrates the measurement uncertainty evaluation of the nonlinear optical angle sensor using a specifically trained MLP-ANN and thereby confirms the feasibility of the proposed GUM-based method. Mathematical derivations are provided to obtain the sensitivity coefficients required for uncertainty estimation. Notably, this derivation is one of the most challenging aspects when applying GUM to ANN-based sensors. The uncertainty of the reference instrument used to generate training labels is also considered by incorporating the effects of the ANN training. The proposed method reveals that the measurement uncertainty of the MLP-ANN estimation ranges from 0.555 arcseconds to 30.264 arcseconds across different measurement regions. A detailed discussion of the results is also provided.

  6. Wide-range absolute angle measurement based on a broadband solid etalon fringe using a mode-locked femtosecond laser Peer-reviewed

    DongWook Shin, Hiraku Matsukuma, Ryo Sato, Wei Gao

    Precision Engineering　95　484-494　2025/08

    Publisher: Elsevier BV

    DOI： 10.1016/j.precisioneng.2025.05.012 　

    ISSN： 0141-6359

  7. Conjugate differential self-calibration of a large-scale two-dimensional variable-line-spacing grating for an absolute optical encoder using a Fizeau phase-shifting interferometer Peer-reviewed

    Chenguang Yin, Xin Xiong, Ryo Sato, Hiraku Matsukuma, Hideaki Tamiya, Wei Gao

    Measurement Science and Technology　36　(7)　075023-075023　2025/07/22

    Publisher: IOP Publishing

    DOI： 10.1088/1361-6501/adee34 　

    ISSN： 0957-0233

    eISSN： 1361-6501

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    Abstract In this paper, a conjugate differential self-calibration method is proposed for fast evaluation of pitch variation in two-dimensional (2D) large-scale variable-line-spacing (VLS) gratings using a Fizeau phase-shifting interferometer. In the novel method, the original and two orthogonally conjugate positions are established through small lateral translations for measuring differential diffracted wavefronts from the target VLS grating. Arithmetic operations on these wavefronts at the three positions are employed to mitigate the influence of noise and tilt errors, elevating the accuracy of retrieving VLS parameters that characterize the pitch variation. Simulations were conducted considering different conditions, and experiments were performed using a Fizeau phase-shifting interferometer to evaluate the VLS parameters of a large-scale 2D VLS grating. The obtained VLS parameters showed strong consistency with those derived from the interferometric stitching measurement. Additionally, a comparison was performed between the reconstructed accumulative errors based on the VLS parameters retrieved by the proposed method and the reading errors of an absolute encoder using the VLS grating, showing the error difference within ±18 nm in the X-direction and ±35 nm in the Y-direction across a 100 mm scanning range, respectively.

  8. A two-axis Lloyd's mirror interferometer with elastically bent mirrors for fabrication of variable-line-spacing scale gratings Peer-reviewed

    Chenguang Yin, Ryo Sato, Satoshi Kodaka, Hiraku Matsukuma, Wei Gao

    Precision Engineering　94　623-637　2025/06

    Publisher: Elsevier BV

    DOI： 10.1016/j.precisioneng.2025.03.029 　

    ISSN： 0141-6359

  9. Near-common-optical-path two-axis surface encoder with a three-layer gratings interference method Peer-reviewed

    Yifan Hong, Ryo Sato, Zhiyang Zhang, Hiraku Matsukuma, Eberhard Manske, Wei Gao

    Optics Express　33　(9)　19951-19951　2025/05/01

    Publisher: Optica Publishing Group

    DOI： 10.1364/oe.552038 　

    eISSN： 1094-4087

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    A near-common-optical-path two-axis surface encoder design is proposed for in-plane and out-of-plane wide-range displacement measurement. A three-layer gratings (TLGs) interference method is newly adopted in the optical design, contributing to a near-common-optical-path for interference beams to improve robustness against environmental disturbances, which had not been realized by conventional surface encoders in out-of-plane Z-axis displacement measurement based on the Michelson interference method. An incident beam is divided into two beams in positive and negative directions at the first layer of transparent grating. At both the positive and negative directions of the second layer of transparent grating, two diffracted beams are generated. One of the diffracted beams incidents on the third layer of scale grating perpendicularly, and the other incidents on the third layer of scale grating at a Littrow angle. The two diffracted beams in each direction then diffracted back to the second layer of transparent grating along the same optical path and superimposed with each other, generating interference signals at each direction, which are received within the sensor head. By calculating the interference signals, two-axis displacement can be obtained simultaneously. A prototype surface encoder is constructed to demonstrate the effectiveness of the proposed TLGs interference method.

  10. A non-Michelson type three-axis grating interferometer using linear scale gratings Peer-reviewed

    Ryo Sato, Yifan Hong, Hiraku Matsukuma, Wei Gao

    CIRP Annals　74　(1)　691-695　2025

    Publisher: Elsevier BV

    DOI： 10.1016/j.cirp.2025.03.011 　

    ISSN： 0007-8506

  11. An absolute surface encoder employing a mode-locked femtosecond laser Invited

    Ryo Sato, Hiraku Matsukuma, Wei Gao

    Holography, Diffractive Optics, and Applications XIV　47-47　2024/11/23

    Publisher: SPIE

    DOI： 10.1117/12.3035032 　

  12. Improvement of angle measurement sensitivity using second harmonic wave interference Peer-reviewed

    Jiahui Lin, Hiraku Matsukuma, Kuangyi Li, Ryo Sato, Wei Gao

    Optics Express　32　(23)　40915-40915　2024/10/25

    Publisher: Optica Publishing Group

    DOI： 10.1364/oe.537872 　

    eISSN： 1094-4087

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    This paper presents the angular displacement measurement based on second harmonic generation (SHG). In our previous study, the angular resolution of sub-arcsecond was achieved. In this paper, three kinds of sensors based on SHG are reported. In these three sensors, the angular displacement is determined from the intensity of the SHG signal since the SHG is sensitive to the angle of the incident light. Two of these sensors in this study utilize the interference of SHG to improve the sensitivity performance. Comparing with the sensors which have been studied before, interference type sensors in this study allow the femtosecond laser to pass through the nonlinear optical crystal twice, which leads to a significant sensitivity improvement. The principles were verified by both simulation and experiment. In the simulation part, the sensitivities of these three kinds of sensors are compared. In the experiment, the sensitivities were confirmed to be consistent with the simulation. Additionally, the resolution of the presented systems is evaluated and sub-0.1-arcsecond is achieved.

  13. Design and testing of a two-axis surface encoder with a single Littrow configuration of a first-order diffraction beam Peer-reviewed

    Yifan Hong, Ryo Sato, Hiraku Matsukuma, Wei Gao

    Precision Engineering　91　577-586　2024/10

    Publisher: Elsevier BV

    DOI： 10.1016/j.precisioneng.2024.10.019 　

    ISSN： 0141-6359

  14. A dual-detection chromatic confocal probe employing a mode-locked femtosecond laser Invited

    Ryo Sato, Chen Li, Hiraku Matsukuma, Wei Gao

    Optical Manufacturing and Testing 2024　1-1　2024/09/30

    Publisher: SPIE

    DOI： 10.1117/12.3026365 　

  15. An Improved Data Processing Algorithm for Spectrally Resolved Interferometry Using a Femtosecond Laser Peer-reviewed

    Tao Liu, Hiraku Matsukuma, Amane Suzuki, Ryo Sato, Wei Gao

    Sensors　24　(9)　2869-2869　2024/04/30

    Publisher: MDPI AG

    DOI： 10.3390/s24092869 　

    eISSN： 1424-8220

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    Spectrally resolved interferometry utilizing a femtosecond laser is widely employed for absolute distance measurement. However, deviations in the output time pulse of the conventional algorithm through inverse Fourier transform are inevitable. Herein, an improved data processing algorithm employing a time-shifting parameter is proposed to improve the accuracy of spectrally resolved interferometry. The principle of the proposed time-shifting algorithm is analyzed theoretically after clarifying the deviation source of the conventional algorithm. Simulation and experimental work were conducted to indicate the improvement in the accuracy of the output absolute distance. The results demonstrated that the proposed algorithm could reduce the deviation of output distances towards the reference values, reaching 0.58 μm by half compared to the conventional algorithm. Furthermore, the measurement uncertainty was evaluated using the Guide to the Expression of Uncertainty in Measurement (GUM), resulting in an expanded uncertainty of 0.71 μm with a 95% confidence.

  16. Design of an Optical Head with Two Phase-Shifted Interference Signals for Direction Detection of Small Displacement in an Absolute Surface Encoder Peer-reviewed

    Ryo Sato, Tao Liu, Satoru Maehara, Ryota Okimura, Hiraku Matsukuma, Wei Gao

    International Journal of Automation Technology　18　(2)　249-256　2024/03/05

    DOI： 10.20965/ijat.2024.p0249 　

  17. Enhanced Data-Processing Algorithms for Dispersive Interferometry Using a Femtosecond Laser Peer-reviewed

    Tao Liu, Hiraku Matsukuma, Amane Suzuki, Ryo Sato, Wei Gao

    Sensors　24　(2)　370-370　2024/01/08

    Publisher: MDPI AG

    DOI： 10.3390/s24020370 　

    eISSN： 1424-8220

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    Dispersive interferometry based on a femtosecond laser is extensively utilized for achieving absolute distance measurements with high accuracy. However, this method cannot measure arbitrary distances without encountering a dead zone, and deviations in its output results are inevitable due to inherent theory limitations. Therefore, two enhanced data-processing algorithms are proposed to improve the accuracy and reduce the dead zone of dispersive interferometry. The principles of the two proposed algorithms, namely the truncated-spectrum algorithm and the high-order-angle algorithm, are proposed after explaining the limitations of conventional methods. A series of simulations were conducted on these algorithms to show the improved accuracy of measurement results and the elimination of the dead zone. Furthermore, an experimental setup based on a dispersive interferometer was established for the application of these proposed algorithms to the experimental interference spectral signals. The results demonstrated that compared with the conventional algorithm, the proposed truncated-spectrum algorithm could reduce the output distance deviations derived from direct inverse Fourier transforming by eight times to reach as low as 1.3 μm. Moreover, the unmeasurable dead zone close to the zero position of the conventional algorithm, i.e., the minimum working distance of a dispersive interferometer, could be shortened to 22 μm with the implementation of the proposed high-order-angle algorithm.

  18. Repetition Frequency Control of a Mid-Infrared Ultrashort Pulse Laser Peer-reviewed

    Hiraku Matsukuma, Masashi Nagaoka, Hisashi Hirose, Ryo Sato, Yuki Shimizu, Wei Gao

    International Journal of Automation Technology　18　(1)　84-91　2024/01/05

    Publisher: Fuji Technology Press Ltd.

    DOI： 10.20965/ijat.2024.p0084 　

    ISSN： 1881-7629

    eISSN： 1883-8022

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    In this study, a method for controlling the repetition frequency of a mid-infrared ultrashort pulse laser with a central wavelength of 2.8 µm is developed. A ring cavity that is insensitive to the polarization state of the laser light emitted from the fiber end was constructed to stabilize the oscillation of the mid-infrared ultrashort pulse laser. More oscillation conditions for the ultrashort pulse laser based on nonlinear polarization rotation are found than the conventional method. To confirm that the pulse oscillation is mode-locked, ultrashort pulse oscillation was confirmed by an autocorrelator. The pulse repetition frequency of this robust ultrashort pulse laser was controlled. The control method was based on the phase-locked loop (PLL) control. A wedge window was inserted into the cavity and mounted on a linear stage driven by a piezoelectric transducer. By driving the piezoelectric transducer, the position of the wedge window changed, and the resulting optical path length also changed. The repetition frequency was controlled based on this principle. Optical path length control by the wedge window and temperature control provides an Allan deviation of approximately 1 mHz.

  19. On-Machine Calibration of Pitch Deviations of a Linear Scale Grating by Using a Differential Angle Sensor Peer-reviewed

    Jiucheng Wu, Yifang Hong, Dong Wook Shin, Ryo Sato, Lue Quan, Hiraku Matsukuma, Wei Gao

    International Journal of Automation Technology　18　(1)　4-10　2024/01/05

    DOI： 10.20965/ijat.2024.p0004 　

  20. Angle Measurement Based on Second Harmonic Generation Using Artificial Neural Network Peer-reviewed

    Kuangyi Li, Zhiyang Zhang, Jiahui Lin, Ryo Sato, Hiraku Matsukuma, Wei Gao

    Nanomanufacturing and Metrology　6　(1)　2023/12

    DOI： 10.1007/s41871-023-00206-5 　

    ISSN： 2520-811X

  21. Autocollimation employing optical frequency comb Peer-reviewed

    H. Matsukuma, K. Ikeda, R. Sato, W. Gao

    Optical Technology and Measurement for Industrial Applications Conference　2023/09/20

    Publisher: SPIE

    DOI： 10.1117/12.3005523 　

  22. Improved peak-to-peak method for cavity length measurement of a Fabry-Perot etalon using a mode-locked femtosecond laser Peer-reviewed

    Dong Wook Shin, Hiraku Matsukuma, Ryo Sato, Eberhard Manske, Wei Gao

    Optics Express　31　(16)　25797-25814　2023/07/31

    DOI： 10.1364/OE.493507 　

    eISSN： 1094-4087

  23. Improved Algorithms of Data Processing for Dispersive Interferometry Using a Femtosecond Laser Peer-reviewed

    Tao Liu, Jiucheng Wu, Amane Suzuki, Ryo Sato, Hiraku Matsukuma, Wei Gao

    Sensors　23　(10)　2023/05

    DOI： 10.3390/s23104953 　

    ISSN： 1424-8220

  24. Investigation of Angle Measurement Based on Direct Third Harmonic Generation in Centrosymmetric Crystals Peer-reviewed

    Kuangyi Li, Jiahui Lin, Zhiyang Zhang, Ryo Sato, Hiroki Shimizu, Hiraku Matsukuma, Wei Gao

    Applied Sciences (Switzerland)　13　(2)　2023/01

    DOI： 10.3390/app13020996 　

    eISSN： 2076-3417

  25. Fabry-Pérot angle sensor using a mode-locked femtosecond laser source Peer-reviewed

    Dong Wook Shin, Hiraku Matsukuma, Ryo Sato, Wei Gao

    Optics Express　30　(26)　46366-46382　2022/12/19

    DOI： 10.1364/OE.477435 　

    eISSN： 1094-4087

  26. Self-Calibration of a Large-Scale Variable-Line-Spacing Grating for an Absolute Optical Encoder by Differencing Spatially Shifted Phase Maps from a Fizeau Interferometer Peer-reviewed

    Xin Xiong, Chenguang Yin, Lue Quan, Ryo Sato, Hiraku Matsukuma, Yuki Shimizu, Hideaki Tamiya, Wei Gao

    Sensors　22　(23)　2022/12

    DOI： 10.3390/s22239348 　

    ISSN： 1424-8220

  27. Reduction of Crosstalk Errors in a Surface Encoder Having a Long Z-Directional Measuring Range Peer-reviewed

    Yifan Hong, Ryo Sato, Yuki Shimizu, Hiraku Matsukuma, Hiroki Shimizu, Wei Gao

    Sensors　22　(23)　2022/12

    DOI： 10.3390/s22239563 　

    ISSN： 1424-8220

  28. Design and Testing of a Compact Optical Angle Sensor for Pitch Deviation Measurement of a Scale Grating with a Small Angle of Diffraction Peer-reviewed

    Lue Quan, Yuki Shimizu, Ryo Sato, Dong Wook Shin, Hiraku Matsukuma, Andreas Archenti, Wei Gao

    International Journal of Automation Technology　16　(5)　572-581　2022/09

    DOI： 10.20965/ijat.2022.p0572 　

    ISSN： 1881-7629

    eISSN： 1883-8022

  29. A Second Harmonic Wave Angle Sensor with a Collimated Beam of Femtosecond Laser Peer-reviewed

    Wijayanti Dwi Astuti, Kuangyi Li, Ryo Sato, Hiraku Matsukuma, Yuki Shimizu, Wei Gao

    Applied Sciences (Switzerland)　12　(10)　2022/05/02

    DOI： 10.3390/app12105211 　

    eISSN： 2076-3417

  30. Influence of Surface Tilt Angle on a Chromatic Confocal Probe with a Femtosecond Laser Peer-reviewed

    Ryo Sato, Yuki Shimizu, Hiraku Matsukuma, Wei Gao

    Applied Sciences (Switzerland)　12　(9)　2022/05/01

    DOI： 10.3390/app12094736 　

    eISSN： 2076-3417

  31. A New Optical Configuration for the Surface Encoder with an Expanded Z-Directional Measuring Range Peer-reviewed

    Yifan Hong, Ryo Sato, Yuki Shimizu, Hiraku Matsukuma, Wei Gao

    Sensors　22　(8)　2022/04

    DOI： 10.3390/s22083010 　

    ISSN： 1424-8220

  32. Theoretical Investigation for Angle Measurement Based on Femtosecond Maker Fringe Peer-reviewed

    Kuangyi Li, Wijayanti Dwi Astuti, Ryo Sato, Hiraku Matsukuma, Wei Gao

    Applied Sciences (Switzerland)　12　(7)　2022/04

    DOI： 10.3390/app12073702 　

    eISSN： 2076-3417

  33. Theoretical investigation of angle measurement based on third-harmonic generation (THG) with a femtosecond laser Peer-reviewed

    Kuangyi Li, Jiahui Lin, Wijayanti Dwi Astuti, Ryo Sato, Hiraku Matsukuma, Wei Gao

    nanoMan 2022 and AETS 2022 - 2022 8th International Conference on Nanomanufacturing and 4th AET Symposium on ACSM and Digital Manufacturing　2022

    DOI： 10.1109/Nanoman-AETS56035.2022.10119491 　

  34. Theoretical Analysis on Gauge Block Length Measurement by Excess Fraction method Peer-reviewed

    Tao Liu, Jiucheng Wu, Ryo Sato, Hiraku Matsukuma, Wei Gao

    nanoMan 2022 and AETS 2022 - 2022 8th International Conference on Nanomanufacturing and 4th AET Symposium on ACSM and Digital Manufacturing　2022

    DOI： 10.1109/Nanoman-AETS56035.2022.10119521 　

  35. Measurement range expansion of chromatic confocal probe with supercontinuum light source Peer-reviewed

    Hiraku Matsukuma, Ryo Sato, Yuki Shimizu, Wei Gao

    International Journal of Automation Technology　15　(4)　529-536　2021

    DOI： 10.20965/ijat.2021.p0529 　

    ISSN： 1881-7629

    eISSN： 1883-8022

  36. An off-axis differential method for improvement of a femtosecond laser differential chromatic confocal probe Peer-reviewed

    Chong Chen, Yuki Shimizu, Ryo Sato, Hiraku Matsukuma, Wei Gao

    Applied Sciences (Switzerland)　10　(20)　1-15　2020/10/02

    DOI： 10.3390/app10207235 　

    eISSN： 2076-3417

  37. Profile measurement by using a femtosecond laser chromatic confocal probe

    Ryo Sato, Yuki Shimizu, Hiraku Matsukuma, Wei Gao

    JSME 2020 Conference on Leading Edge Manufacturing/Materials and Processing, LEMP 2020　2020

    DOI： 10.1115/LEMP2020-8626 　

  38. Investigation and Improvement of Thermal Stability of a Chromatic Confocal Probe with a Mode-Locked Femtosecond Laser Source Peer-reviewed

    Ryo Sato, Yuki Shimizu, Chong Chen, Hiraku Matsukuma, Wei Gao

    Applied Sciences　9　(19)　4084-4084　2019/09/30

    Publisher: MDPI AG

    DOI： 10.3390/app9194084 　

    eISSN： 2076-3417

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    An intentional investigation on the thermal stability of a mode-locked femtosecond laser chromatic confocal probe, which is a critical issue for the probe to be applied for long-term displacement measurement or surface profile measurement requiring long-time scanning, is carried out. At first, the thermal instability of the first prototype measurement setup is evaluated in experiments where the existence of a considerably large thermal instability is confirmed. Then the possible reasons for the thermal instability of the measurement setup are analyzed quantitatively, such as the thermal instability of the refractive index of the confocal lens and the thermal expansion of mechanical jigs employed in the probe. It is verified that most of the thermal instability of the measurement setup is caused by the thermal expansion of mechanical jigs in the probe. For the improvement of the thermal stability of the probe, it is necessary to employ a low thermal expansion material for the mechanical jigs in the measurement setup and to shorten the optical path length of the laser beam. Based on the analysis result, a second prototype probe is newly designed and constructed. The improved thermal stability of the second prototype probe is verified through theoretical calculations and experiments.

  39. A Method for Expansion of Z-Directional Measurement Range in a Mode-Locked Femtosecond Laser Chromatic Confocal Probe Peer-reviewed

    Chong Chen, Ryo Sato, Yuki Shimizu, Taku Nakamura, Hiraku Matsukuma, Wei Gao

    Applied Sciences　9　(3)　454-454　2019/01/29

    Publisher: MDPI AG

    DOI： 10.3390/app9030454 　

    eISSN： 2076-3417

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    A method is proposed to expand the Z-directional measurement range of a fiber-based dual-detector chromatic confocal probe with a mode-locked femtosecond laser source. In the dual-detector chromatic confocal probe, the Z-directional displacement of a measurement target is derived from the peak wavelength in the normalized intensity ratio from the two light intensities obtained by the two identical fiber detectors. In this paper, a new method utilizing the main-lobe and side-lobes of axial responses acquired from both the normalized intensity ratio Ia and the invert normalized intensity ratio In, which is the inverse of Ia, is proposed to obtain the seamless relationship between the peak wavelength and the Z-directional displacement of a measurement target. Theoretical calculations and experimental investigation are carried out to demonstrate the feasibility of the proposed measurement range expansion method.

  40. Theoretical investigation on measurement range of a femtosecond laser chromatic confocal probe by utilizing side-lobe of axial response Peer-reviewed

    Chong Chen, Hiraku Matsukuma, Ryo Sato, Xiuguo Chen, Yuki Shimizu, Wei Gao

    2018 IEEE International Conference on Advanced Manufacturing (ICAM)　2018/11

    Publisher: IEEE

    DOI： 10.1109/amcon.2018.8615064 　

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Misc. 12

  1. 精密位置決めのための多軸計測用センサの一括化 Invited

    佐藤 遼, 高 偉

    機械設計　68　(11)　21-27　2024/10

  2. モード同期フェムト秒レーザを用いた絶対位置エンコーダに関する研究−原理検証と基礎特性評価に関する検討−

    佐藤 遼, 松隈 啓, 高 偉

    2024年度精密工学会秋季大会学術講演会論文集　2024/09

  3. 光周波数コムを用いた角度計測に対する自律校正法の開発

    松隈 啓, 佐藤 遼, 高 偉

    2024年度精密工学会秋季大会学術講演会論文集　2024/09

  4. 中赤外超短パルスレーザによる透明材料加工

    松隈 啓, 廣瀬 久志, 佐藤 遼, 高 偉

    2024年度精密工学会春季大会学術講演会論文集　408　2024/03

    DOI： 10.11522/pscjspe.2024S.0_408 　

  5. モード同期フェムト秒レーザを用いた絶対位置エンコーダに関する研究ー原理提案と理論数値計算に基づく検討ー

    佐藤 遼, 松隈 啓, 高 偉

    2023年度精密工学会秋季大会学術講演会論文集　601-602　2023/09

    DOI： 10.11522/pscjspe.2023A.0_601 　

  6. モード同期中赤外レーザーの繰返周波数制御に関する研究

    松隈 啓, 長岡 将司, 廣瀬 久志, 佐藤 遼, 高 偉

    2023年度精密工学会秋季大会学術講演会論文集　539　2023/09

    DOI： 10.11522/pscjspe.2023A.0_539 　

  7. 第二次高調波共焦点プローブに関する研究 -角度計測に関する検討-

    佐藤 遼, 清水 裕樹, 清水 浩貴, 松隈 啓, 高 偉

    2023年度精密工学会春季大会学術講演会論文集　412-413　2023/09

  8. Precision measurement on machine tools Invited

    67　(6)　329-332　2023/06

  9. デュアルコム分光オートコリメーション による精密角度変位計測

    松隈 啓, 池田 翔, 佐藤 遼, 高 偉

    2023年度精密工学会春季大会学術講演会論文集　409　2023/03

    DOI： 10.11522/pscjspe.2023S.0_409 　

  10. モード同期フェムト秒レーザ共焦点プローブに関する研究 ー極小点追跡法を用いた合焦波長検出に関する検討ー

    佐藤 遼, 松隈 啓, 清水 裕樹, 高 偉

    2021年度精密工学会学術講演会講演論文集　585-586　2021/09

    DOI： 10.11522/pscjspe.2021A.0_585 　

  11. Confocal probe employing a mode-locked femtosecond laser Invited

    Optical Alliance　31　(2)　47-51　2020/02

  12. Theoretical investigation on measurement range expansion of a femtosecond laser chromatic confocal probe

    Chong Chen, Hiraku MATSUKUMA, Ryo SATO, Yuki SHIMIZU, Wei GAO

    The Proceedings of Conference of Tohoku Branch　2019.54　146-146　2019

    Publisher: Japan Society of Mechanical Engineers

    DOI： 10.1299/jsmeth.2019.54.146 　

    eISSN： 2424-2713

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Presentations 15

  1. Investigation of a Signal Processing Method Based on a Dual-Detection Chromatic Confocal Probe Invited

    Ryo Sato, Chen Li, Hiraku Matsukuma, Wei Gao

    The 9th International Conference on Nanomanufacturing (nanoMAN2024)　2024/12/03

  2. Second harmonic confocal probe with a mode-locked femtosecond laser Invited

    Ryo Sato, Hiraku Matsukuma, Wei Gao

    The 20th International Conference of Precision Engineering (ICPE2024)　2024/10/24

  3. An absolute surface encoder employing a mode-locked femtosecond laser Invited

    Ryo Sato, Hiraku Matsukuma, Wei Gao

    SPIE/COS Photonics Asia (Holography, Diffractive Optics, and Applications XIV)　2024/10/14

  4. モード同期フェムト秒レーザを用いた絶対位置エンコーダに関する研究−原理検証と基礎特性評価に関する検討−

    佐藤 遼, 松隈 啓, 高 偉

    2024年度精密工学会秋季大会学術講演会　2024/09/04

  5. A dual-detection chromatic confocal probe employing a mode-locked femtosecond laser Invited

    Ryo Sato, Chen Li, Hiraku Matsukuma, Wei Gao

    SPIE. OPTICS+PHOTONICS　2024/08/20

  6. Investigation of angle measurement based on confocal probe employing second harmonic generation

    Ryo Sato, Yuki Shimiz, Hiraku Matsukuma, Wei Gao

    The 15th International Symposium on Measurement Technology and Intelligent Instruments (ISMTII2023)　2023/09/19

  7. モード同期フェムト秒レーザを用いた絶対位置エンコーダに関する研究ー原理提案と理論数値計算に基づく検討ー

    佐藤 遼, 松隈 啓, 高 偉

    2023年度精密工学会秋季大会学術講演会　2023/09/15

  8. 第二次高調波共焦点プローブに関する研究 -角度計測に関する検討-

    佐藤 遼, 清水 裕樹, 清水 浩貴, 松隈 啓, 高 偉

    2023年度精密工学会春季大会学術講演会　2023/03/15

  9. Investigation of Measurement Range of a Differential Chromatic Confocal Probe employing a Mode-Locked Femtosecond Laser

    Ryo Sato, Hiraku Matsukuma, Yuki Shimizu, Wei Gao, Andreas Fischer

    The 10th International Conference on Leading Edge Manufacturing in 21st Century(LEM21)　2021/11/17

  10. モード同期フェムト秒レーザ共焦点プローブに関する研究-極小点追跡法を用いた合焦波長検出に関する検討-

    佐藤 遼, 松隈 啓, 清水 裕樹, 高 偉

    2021年度精密工学会秋季大会学術講演会　2020/09/21

  11. Profile Measurement by Using a Femtosecond Laser Chromatic Confocal Probe

    Ryo Sato, Yuki Shimizu, Hiraku Matsukuma, Wei Gao

    The International Conference on Leading Edge Manufacturing/Materials and Processing (LEMP2020)　2020/09/03

  12. Analysis of temperature influence on a chromatic confocal probe with a mode-locked femtosecond laser

    Ryo Sato, Yuki Shimizu, Hiraku Matsukuma, Wei Gao

    The 14th Internartional Symposium on Measurement Technology and Intelligent Instruments　2019/09/02

  13. モード同期フェムト秒レーザ共焦点プローブに関する研究 -測定対象物チルト角が極小点追跡法へ与える影響の調査-

    佐藤 遼, 松隈 啓, 高 偉

    2022年度精密工学会東北支部学術講演会　2022/11/12

  14. フェムト秒レーザを用いた共焦点顕微鏡における光軸変位計測高安定化に関する研究

    佐藤 遼,松隈 啓,清水 裕樹,高 偉

    2019年度精密工学会東北支部学術講演会　2019/11/09

  15. フェムト秒レーザを用いた共焦点顕微鏡の温度安定性に関する研究

    佐藤 遼, 松隈 啓, 陳 衝, 清水 裕樹, 高 偉

    2018年度精密工学会東北支部学術講演会　2018/11/24

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Research Projects 6

  1. 非線形光学フィルタリング共焦点プローブによる次世代ピコメートル級走査式形状計測

    佐藤 遼

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 若手研究

    Institution: 東北大学

    2025/04/01 - 2028/03/31

  2. 光周波数コムを用いたピコラジアン級次世代ファブリペロー絶対角度計測法の創出

    高 偉, 佐藤 遼

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(B)

    Institution: 東北大学

    2024/04/01 - 2027/03/31

  3. ピコメートル精度加工を実現するエンコーダ用回折格子のリアルタイム機上「絶対」格子ピッチ計測法の開発

    佐藤 遼

    Offer Organization: 公益社団法人 大澤科学技術振興財団

    System: 2024年度研究助成

    Institution: 東北大学

    2024/10 - 2025/10

  4. Surface encoders for multi-axis displacement measurement with a scale grating

    佐藤 遼

    Offer Organization: 公益社団法人 三豊科学技術振興協会

    System: 国際交流「渡航」助成

    Category: 国際会議参加

    2025/05 -

  5. An absolute surface encoder employing a mode-locked femtosecond laser

    佐藤 遼

    Offer Organization: 公益社団法人 三豊科学技術振興協会

    System: 国際交流「渡航」助成

    Category: 国際会議参加

    Institution: 東北大学

    2024/10 -

  6. 光周波数コムの次元変換で実現する次世代XYZ3軸「絶対」位置極高精度計測への挑戦

    佐藤 遼

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 特別研究員奨励費

    Institution: 東北大学

    2023/03/08 - 2024/03/31

    More details Close

    本研究では，不等ピッチ2軸格子の分光次元変換作用をもとに，光コムからXY2軸位置コムを創出し，これまでに構築しているZ位置コムと融合することで，従来は困難であった国家標準に直結した形態で信頼性が保証された極高精度多軸「絶対」位置検出を実現することが本研究の目的である． まず，XY位置コムとの融合に向け，これまでに開発しているZ絶対位置コム光学系に対してレーザオートコリメーション法の原理を新たに導入し，測定面傾斜角に影響を受けないZ位置計測の実現を検討する．その後，「不等ピッチ」2軸格子の分光作用により計測点のXY軸絶対位置情報を±1次反射回折光デジタル光周波数に次元変換し差動検出するとともに，±1次光で生成する光干渉信号を用いてXY2軸絶対位置を極高感度検出する，XY絶対位置コム光学系を構築する．最後に，上記2つの光学系を組み合わせてXYZ3軸「絶対」位置コムを構築し，その性能を実験的に明らかにする． 計画2年目となる令和4年度は，当初の計画とおり，昨年度に構築を行った光ファイバーベースの光コム光源を用いたZ絶対位置コムプロトタイプ光学系の設計および構築を行った．プロトタイプ光学系を用いた基礎特性評価を実施し，測定面傾斜角が対象物光軸Z位置測定に与える影響を定量的に評価した．さらに，測定面傾斜角によらず対象物光軸Z位置を高精度に測定可能な新たな原理として，Z位置コムに採用している共焦点光学系の検出器を非線形光学現象である第二次高調波発生(ＳＨＧ)媒体であるBBO結晶へ変更したSHG共焦点光学系を開発した．また，XY絶対位置コムを創出するために，ファイバー内干渉光学系から空間干渉光学系へと変更を行うことで，絶対値平面位置計測の実現可能性を検討した．

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Teaching Experience 4

  1. Seminar Ⅱ　Tohoku University

  2. Laboratory Experiment Ⅰ　Tohoku University

  3. Seminar Ⅰ　Tohoku University

  4. Laboratory Experiment Ⅱ　Tohoku University

Social Activities 1

  1. 第22回 夏休みこども科学キャンパス

    https://www.ip.eng.tohoku.ac.jp/archive/summer.html

    2024/08/07 - 2024/08/08

Media Coverage 2

  1. 東北大学でイベント 実験で知る科学の楽しさ

    仙台放送　FNN Live News days▽全国・宮城の最新ニュース　https://nc.ox-tv.co.jp/news/detail/2024080900002

    2024/08/09

    Type: TV or radio program

  2. IJAT Most Downloaded Papers, Jul. 2024

    FUJI TECHNOLOGY PRESS LTD.　FUJI TECHNOLOGY PRESS LTD.　https://www.fujipress.jp/most_dl/au-dl2024_07/

    2024/07

    Type: Internet