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ABOUT US

We are exploring a new functional transparent glass material utilizing for sustainable society.

CURRENT RESEARCH

Synthesis and characterization of transparent photonics glasses without hazardous elements

Very small stress induced birefringent (photoelastic) oxide glasses for polarization-controlling optical materials

Structural analysis in functional oxide glasses

Lead-free zero/small photoelastic oxide glasses

We have continuously studied a photonics fiber which can utilize for an optical fiber typed current sensor. The important points of the device are hazardou element free such as lead, and are possessing a property of very photoelastic constant of consituent oxide glass.

ZnO containing transparent SnO-P₂O₅ glasses

Binary SnO-SiO₂ glasses

Fiber current sensors working in "smart grid" network

The ability of current sensing depends on the material- photoelastic property of the glass. Our glasses are categorized into lead-free oxide glasses which have very low photoelastic constant.

Faraday effect / photoelastic effect

Faraday effect

The priciple of current sensing is based on Faraday effect. The Faraday rotation angle of linearly polarized light corresponds to the magnetic field along the path followed by the fiber (Fig. 1).

Fig. 1. The Faraday rotation angle of linearly polarized light being in proportion of magnetic field/current.

Photoelastic effect

The signal is linearly correlated to the rotation angle but the sensitivity is drastically reduced by a stress induced birefringence, so called photoelastic effect, which occurs in the situation of the number of turns of fiber which is wounded around the conductor (Fig. 2).

Fig. 2. Rotation of the linearly poralized light due to birefringence caused by photoelastic effect.

Zero photoelastic glass

Therefore, very small birefringent glass fiber having zero photoelastic constant (PEC) is desirable for maintaining its sensitivity to measure the current (Fig. 3).

Fig. 3. The linearly poralized light just only sensitized for magnetic field/current in a glass with a "zero" photoelastic constant.

SAITOH, Akira

E-mail & contact address

saito.akira.mg_at_ehime-u.ac.jp

Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan, Professor

Akira Saitoh received his Ph.D. degree in Material Science and Engineering from Tokyo Institute of Technology (Tokyo Tech), Japan in 2006. Afterwards, he was a post-doctoral researcher in Graduate School of Applied Physics, Hokkaido University. In 2009, He moved to Kitami Institute of Technology as a faculty member in Department of Electrical and Electronic Engineering. In 2011, he joined the Graduate School of Science and Engineering in Ehime University as a faculty member. He has involved in multiple non-crystalline (glassy) material development projects. He also has developed a key oxide glass material with functional and optical characteritics such as small birefringent oxide glasses without hazordous element of lead.

Graduate students advised

T. Shimizu: MS (2022, Advisor)

T. Eguchi: MS (2022, Co-Advisor)

R. Fukuhara: MS (2022, Co-Advisor)

Y. Imagawa: MS (2022, Co-Advisor)

Y. Tomihara: MS (2021, Advisor)

K. Hayashi: MS (2021, Advisor)

T. Okamoto: MS (2020, Advisor)

K. Kishimoto: MS (2020, Advisor)

A. Ihira: (2020, Co-Advisor)

K. Nishimura: (2020, Co-Advisor)

K. Fujii: (2020, Co-Advisor)

K. Suzuki: MS (2019, Advisor)

Y. Hamasaki: MS (2019, Co-Advisor)

M. Fujisawa: MS (2019, Co-Advisor)

K. Suzuki: MS (2019, Co-Advisor)

R. Higaki: MS (2019, Co-Advisor)

M. Itadani: MS (2018, Advisor)

G. Shimada: MS (2018, Co-Advisor)

Y. Takahashi: MS (2018, Co-Advisor)

Y. Hashida: MS (2017, Advisor)

A. Nomura: MS (2017, Co-Advisor)

J. Miki: MS (2017, Co-Advisor)

Y. Kanda: MS (2017, Co-Advisor)

Arman: PhD (2016, Co-Advisor)

Undergraduate students advised

T. Tsujii (2022)

M. Wada (2022)

Y. Watanabe (2022)

T. Akiyama (2021)

M. Sakata (2021)

A. Sakuragi (2021)

D. Takechi (2021)

K. Mitsui (2021)

Y. Kawasaki (2020)

H. Kusunoki (2020)

K. Sakata (2020)

Y. Tamada (2020)

R. Fujisawa (2020)

Y. Ogawa (2019)

T. Shimizu (2019)

Y. Tomihara (2019)

K. Hayashi (2019)

T. Okamoto (2018)

Y. Ohno (2018)

S. Kasahara (2018)

K. Kishimoto (2018)

R. Hayashi (2018)

K. Suzuki (2017)

K. Nakao (2017)

M. Itadani (2016)

Y. Masaoka (2016)

Education/Training

Hokkaido University, Sapporo, Japan; B.A. (Honors); Applied Physics; 2000
Hokkaido University, Sapporo, Japan; M.A.; Applied Physics; 2002
Tokyo Institute of Technology, Tokyo, Japan; Ph.D.; Materials Science and Engineering; 2006

Positions & Employment

2006-2009; Postdoctoral Fellow, Applied Physics， Hokkaido University, Sapporo, Japan
2009-2011; Assistant Professor, Department of Electrical and Electronic Engineering, Kitami Institute of Technology, Kitami, Japan
2011-2016; Assistant Professor, Materials Science and Engineering, Ehime University, Matsuyama, Japan
2016-2019; Associate Professor, Materials Science and Engineering, Ehime University, Matsuyama, Japan
2017-2019; Specially Appointed Associate Professor (concurrent post), Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
2019-present; Professor, Materials Science and Engineering, Ehime University, Matsuyama, Japan
2019-present; Specially Appointed Professor (concurrent post), Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan

Current Scientific Activities

Developments for new transparent phosphate & silicate glass fibers using magneto-optics effect
Basic study of optical & thermal properties in phosphate glasses
Structural study in phosphate, boro-phosphate, borate, and silicate glasses
Process developments in oxide-based slags and ceramics for recycling substances

University and Professional Service

2019- Member, Amorphous and Nano-Crystalline Materials and Applications, 147 th Committee, The Japan Society for Promotion of Science
2017- Program Review Committee, Glass, Micro-crystalline Program, The Japan Society of Applied Physics
2013-2018 Member, Amorphous and Nano-Crystalline Materials, 147 th Committee, The Japan Society for Promotion of Science

Visiting Appointments

2015-2016 Visiting Researcher: LASIR UMR-CNRS, Universite de Lille 1, Lille, France

2015 Visiting Researcher: Instituto de Ceramica y Vidrio, Madrid, Spain

2014 Visiting Scientist: Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, Missouri, USA

Professional Societies

The Japan Society of Applied Physics
The Ceramic Society of Japan
The Mining and Materials Processing Institute of Japan
American Ceramic Society