Prof. Masato Aketagawa Profile

Prof. Masato Aketagawa

Professor at Nagaoka Univ of Technology

SPIE Involvement:

Conference Program Committee | Author

Publications (22)

Proceedings Article | 27 October 2021 Paper

Resolution evaluation of displacement measuring interferometer with sinusoidal phase modulation and modified phase-locked loop

Masato Aketagawa, Masato Higuchi, Tomohiro Sowa, Dong Wei

Proceedings Volume 11927, 119270K (2021) https://doi.org/10.1117/12.2616268

KEYWORDS: Interferometers, Scanning probe microscopy, Phase shift keying, Phase modulation, Field programmable gate arrays, Mirrors, Modulation, Linear filtering, Light sources, Fiber lasers

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Proceedings Article | 27 October 2021 Paper

Noise floor comparison of optical displacement measuring interferometer between air and vacuum environments

Masato Aketagawa, Kousuke Sakasai, Masato Higuchi, Dong Wei, Thanh Nguyen

Proceedings Volume 11927, 119270D (2021) https://doi.org/10.1117/12.2616260

KEYWORDS: Interferometers, Heterodyning, Environmental sensing, Ferroelectric materials, Field programmable gate arrays, Bragg cells, Retroreflectors, Reflectors, Photodetectors, Modulators

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Proceedings Article | 27 October 2021 Paper

Resolution evaluation of displacement measuring interferometer with sinusoidal phase modulation and modified phase-locked loop

Masato Aketagawa, Masato Higuchi, Tomohiro Sowa, Dong Wei

Proceedings Volume 11927, 119270K (2021) https://doi.org/10.1117/12.2616268

KEYWORDS: Interferometers, Scanning probe microscopy, Phase shift keying, Phase modulation, Field programmable gate arrays, Mirrors, Modulation, Linear filtering, Light sources, Fiber lasers

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SPIE Journal Paper | 8 March 2021

Determining a bandpass filter for interfering fringe spectrum extraction using clustering analysis

Dong Wei, Yusuke Nagata, Motohisa Sano, Masato Aketagawa

OE, Vol. 60, Issue 03, 034105, (March 2021) https://doi.org/10.1117/12.10.1117/1.OE.60.3.034105

KEYWORDS: Interference (communication), Fourier transforms, Bandpass filters, Fringe analysis, Signal detection, Optical engineering, Superposition, Mirrors, Interferometry, Interferometers

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Proceedings Article | 21 June 2019 Presentation + Paper

Demodulation for sinusoidal frequency/phase modulation interferometer using artificial harmonic series signal and phase-locked loop

Masato Aketagawa, Masato Higuchi, Dong Wei

Proceedings Volume 11056, 110560F (2019) https://doi.org/10.1117/12.2525200

KEYWORDS: Modulation, Interferometers, Field programmable gate arrays, Demodulation, Frequency modulation, Phase modulation

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A new demodulation method for sinusoidal frequency/phase modulation (SFM/SPM) interferometers using an artificial harmonic series signal and a phase-locked loop (PLL) is proposed in the paper. Utilizing a laser diode (LD) as the light source and an electric optic modulator (EOM), frequency/phase modulations of the LD light can be achieved by modulating the LD injection current or the driving voltage to the EOM. The SFM/SPM interference signals for the displacement measurement has have the form of cos(msinω_mt+θ), where m, ω_m and φ are a modulation index, a modulation frequency and a phase change due to optical path movement, respectively. Therefore, the SFM/SPM interference signals is composed by a series of harmonics of the modulation frequency. The two adjacent (2k and 2k+1: k is integer) harmonics include the displacement information. By using the two harmonics, a Lissajous diagram can be drawn to obtain the displacements. In the conventional way, the two harmonics can be demodulated by two lock-in amplifiers. In this paper, we propose new demodulation method for SFM/SPM interferometers using an artificial hormonic series signal and the PLL, which are installed in field programable gate array (FPGA), to obtain sub-picometer (μrad) resolution. An artificial hormonic signals with the form of sin(msinω_mt+θ) can be made virtually by the FPGA, where θ is the target phase controlled by the PLL. The output signal from the interferometer will be firstly digitized by the FPGA, and the digitized output signal and the artificial harmonic series signal are multiplied by a mixer, then the mixer output signal is inserted to a low pass filter (LPF). Then the LPF output signal should be -sin(φ-θ)~-(φ-θ) (if (φ-θ) is sufficiently small). In the system, modulation index should be fixed to some value. To set the LPF output signal (-(φ-θ)) to null, the target phase θ of the virtual artificial harmonic signal is controlled by the PLL. In the paper, we discuss the principle, experimental system and results.

SPIE Journal Paper | 20 November 2018

Phase information-assisted method to obtain position of zero optical path difference for a pulse-train interferometer

Dong Wei, Yusuke Nagata, Masato Aketagawa

OE, Vol. 57, Issue 11, 114106, (November 2018) https://doi.org/10.1117/12.10.1117/1.OE.57.11.114106

KEYWORDS: Interferometers, Mirrors, Michelson interferometers, Signal processing, Interferometry, Fringe analysis, Pulsed laser operation, Light sources, Fourier transforms, Communication theory

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Proceedings Article | 7 November 2018 Paper

Phase determination method for sinusoidal frequency/phase modulation displacement measuring interferometer

Masato Higuchi, Dong Wei, Masato Aketagawa

Proceedings Volume 10819, 108190C (2018) https://doi.org/10.1117/12.2501026

KEYWORDS: Modulation, Interferometers, Phase measurement, Signal detection, Sensors, Phase modulation

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Proceedings Article | 6 November 2018 Paper

Direct phase determination using simple phase lock loop for heterodyne displacement-measuring interferometers

Thanh-Dong Nguyen, Quang-Anh Duong, Masato Higuchi, Wei Dong, Masato Aketagawa

Proceedings Volume 10819, 1081907 (2018) https://doi.org/10.1117/12.2500626

KEYWORDS: Phase shifts, Interferometers, Heterodyning, Phase shift keying, Phase measurement, Field programmable gate arrays, Linear filtering, Phase modulation, Data storage, Interferometry

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Proceedings Article | 2 November 2018 Paper

Selection of frequency domain filter based on match of different location-specific points

Dong Wei, Kenta Enoki, Masato Aketagawa

Proceedings Volume 10819, 108191F (2018) https://doi.org/10.1117/12.2500637

KEYWORDS: Interferometers, Fringe analysis, Fourier transforms, Distance measurement

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Proceedings Article | 28 May 2018 Paper

Fast and precision displacement/3D profile measuring interferometers using sinusoidal frequency/phase modulation without lock-in amplifiers

Masato Aketagawa, Takehiro Nakagawa, Dong Wei

Proceedings Volume 10695, 106950H (2018) https://doi.org/10.1117/12.2311837

KEYWORDS: Modulation, Interferometers, Frequency modulation, Demodulation, Data acquisition, Signal detection, Phase modulation, Image processing

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Proceedings Article | 28 February 2017 Paper

Uncertainty change in length conversion affected by change in environmental parameters

Dong Wei, Masato Aketagawa

Proceedings Volume 10256, 102560O (2017) https://doi.org/10.1117/12.2256341

KEYWORDS: Environmental sensing, Pulsed laser operation, Frequency combs, Refractive index, Interferometers, Standards development, Femtosecond phenomena, Fiber optic communications, Optical communications, Optical fibers

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Proceedings Article | 24 November 2016 Paper

Spindle error motion measurement using concentric circle grating and sinusoidal frequency-modulated semiconductor lasers

Masato Higuchi, Thanh-Tung Vu, Masato Aketagawa

Proceedings Volume 10023, 1002307 (2016) https://doi.org/10.1117/12.2246235

KEYWORDS: Motion measurement, Spindles, Optical sensors, Interferometers, Modulation, Semiconductor lasers, Frequency modulation, Phase modulation, Mirrors, Sensors

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Proceedings Article | 24 November 2016 Paper

Experimental investigation of correlation between surface amplitude parameters of frosted glass diffuser and size of polishing grit

Dong Wei, Tomoya Katagiri, Masato Aketagawa

Proceedings Volume 10023, 100231M (2016) https://doi.org/10.1117/12.2245645

KEYWORDS: Surface finishing, Diffusers, Glasses, Polishing, Particles, Surface roughness, Optical properties, Radium, Abrasives, Mechanical engineering

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Proceedings Article | 24 September 2015 Paper

Sinusoidal frequency modulation on laser diode for frequency stabilization and displacement measuring interferometry

Masato Aketagawa, Thanh-Tung Vu, Ryo Yamazaki

Proceedings Volume 9628, 96281D (2015) https://doi.org/10.1117/12.2191032

KEYWORDS: Absorption, Modulation, Interferometers, Frequency modulation, Laser stabilization, Signal detection, Semiconductor lasers, Homodyne detection, Molecules, Iodine

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Proceedings Article | 19 February 2015 Paper

Correction of group refraction index based on pulse trains interference

Dong Wei, Masato Aketagawa

Proceedings Volume 9449, 944909 (2015) https://doi.org/10.1117/12.2075504

KEYWORDS: Refractive index, Temperature metrology, Humidity, Numerical simulations, Optical fibers, Interferometry, Turbulence, Frequency combs, Distance measurement, Interferometers

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Proceedings Article | 13 November 2014 Paper

Correction of refraction index based on adjacent pulse repetition interval lengths

Dong Wei, Masato Aketagawa

Proceedings Volume 9276, 92761C (2014) https://doi.org/10.1117/12.2069828

KEYWORDS: Refractive index, Second-harmonic generation, Mirrors, Turbulence, Frequency combs, Harmonic generation, Humidity, Numerical simulations, Atmospheric corrections, Distance measurement

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SPIE Journal Paper | 9 September 2014

Two-color absolute length measuring method based on pulse repetition interval lengths

Dong Wei, Masato Aketagawa, Kiyoshi Takamasu, Hirokazu Matsumoto

OE, Vol. 53, Issue 12, 122413, (September 2014) https://doi.org/10.1117/12.10.1117/1.OE.53.12.122413

KEYWORDS: Mirrors, Refractive index, Distance measurement, Interferometers, Optical fibers, Second-harmonic generation, Frequency combs, Temperature metrology, Humidity, Optical testing

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SPIE Journal Paper | 11 July 2014

Analysis of the second harmonic generation of a femtosecond optical frequency comb

Dong Wei, Masato Aketagawa

OE, Vol. 53, Issue 12, 122604, (July 2014) https://doi.org/10.1117/12.10.1117/1.OE.53.12.122604

KEYWORDS: Second-harmonic generation, Harmonic generation, Frequency combs, Femtosecond phenomena, Signal detection, Optical amplifiers, Polarization, Dielectric polarization, Optical engineering, Optical fibers

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SPIE Journal Paper | 2 December 2013

Characteristics of an adjacent pulse repetition interval length as a scale for length

Dong Wei, Masato Aketagawa

OE, Vol. 53, Issue 05, 051502, (December 2013) https://doi.org/10.1117/12.10.1117/1.OE.53.5.051502

KEYWORDS: Refractive index, Neon, Standards development, Optical fibers, Environmental sensing, Frequency combs, Humidity, Protactinium, Optical testing, Laser stabilization

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Proceedings Article | 20 November 2012 Paper

Spindle error motion measurement using concentric circle grating and phase modulation interferometers

M. Aketagawa, M. Madden, S. Uesugi, T. Kumagai, Y. Maeda, E. Okuyama

Proceedings Volume 8563, 85630C (2012) https://doi.org/10.1117/12.2000812

KEYWORDS: Motion measurement, Spindles, Interferometers, Optical sensors, Diffraction gratings, Phase modulation, Diffraction, Signal detection, Mirrors, Modulation

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Proceedings Article | 3 October 2008 Paper

Measurement of air-refractive-index fluctuation from frequency change using phase modulation homodyne interferometer and external cavity laser diode

Masato Aketagawa, Yuta Hoshino, Masashi Ishige, Tuan Banh Quoc

Proceedings Volume 7155, 71551V (2008) https://doi.org/10.1117/12.814568

KEYWORDS: Interferometers, Semiconductor lasers, Temperature metrology, Phase modulation, Homodyne detection, Sensors, Environmental sensing, Humidity, Laser stabilization, Digital signal processing

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Proceedings Article | 22 September 1993 Paper

Geometrical accuracy measurement for large-scale steel bridge members

Koji Takada, Masato Aketagawa, Kunio Torii, Shoji Ogawa, Yoshitaka Kozakura

Proceedings Volume 2101, (1993) https://doi.org/10.1117/12.156499

KEYWORDS: Bridges, Inspection, Composites, Stereo vision systems, Cameras, CCD cameras, Calibration, Computing systems, Sensors, Computer simulations

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Showing 5 of 22 publications

Conference Committee Involvement (16)

Optical Metrology and Inspection for Industrial Applications XI

12 October 2024 | Nantong, Jiangsu, China

Optical Technology and Measurement for Industrial Applications Conference

22 April 2024 | Yokohama, Japan

Optical Metrology and Inspection for Industrial Applications X

15 October 2023 | Beijing, China

Optical Technology and Measurement for Industrial Applications Conference

17 April 2023 | Yokohama, Japan

Optical Metrology and Inspection for Industrial Applications IX

5 December 2022 | Online Only, China

Optical Technology and Measurement for Industrial Applications Conference 2022

18 April 2022 | Yokohama, Japan

Optical Metrology and Inspection for Industrial Applications VIII

11 October 2021 | Nantong, JS, China

Optical Technology and Measurement for Industrial Applications Conference

20 April 2021 | Online, Japan

Optical Metrology and Inspection for Industrial Applications VII

12 October 2020 | Online Only, China

Optical Technology and Measurement for Industrial Applications Conference

22 April 2020 | Yokohama, Japan

Optical Metrology and Inspection for Industrial Applications VI

21 October 2019 | Hangzhou, China

Optical Technology and Measurement for Industrial Applications Conference

23 April 2019 | Yokohama, Japan

Optical Metrology and Inspection for Industrial Applications V

11 October 2018 | Beijing, China

Optical Metrology and Inspection for Industrial Applications IV

12 October 2016 | Beijing, China

Optical Metrology and Inspection for Industrial Applications III

9 October 2014 | Beijing, China

Optical Metrology and Inspection for Industrial Applications II

5 November 2012 | Beijing, China

Showing 5 of 16 Conference Committees

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