Development of an ideal method for measuring electric fields in gases using second harmonic generation by ultrashort pulsed lasers

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K18709
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 21:Electrical and electronic engineering and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Kumada Akiko 東京大学, 大学院工学系研究科(工学部), 教授 (20313009)
• Co-Investigator(Kenkyū-buntansha): 佐藤 正寛 東京大学, 大学院工学系研究科(工学部), 准教授 (40805769) ; 藤井 隆 東京大学, 大学院工学系研究科(工学部), 特任教授 (60371283)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 電界計測 / 二次高調波 / ラプラス場 / 逆計算 / 位相整合

Outline of Final Research Achievements

The aim of this study is to realise an ideal electric field measurement method that can measure the three-dimensional distribution of the vector components of the electric field in Laplace and Poisson fields non-contact, non-invasively and with high spatial resolution, using the electric field-induced second harmonic generation (E-FISHG) due to the third-order non-linear susceptibility of gas polarisation. The SH is generated by focusing a laser beam with a lens to a sufficient intensity, and a data sequence is obtained by translating the lens and shifting the focus in the direction of laser propagation, and then performing a reverse calculation based on the laser beam shape information that has been measured or calculated in advance,to spatially resolve the applied electric filed in the beam propagation direction as well.

Free Research Field

電気電子工学

Academic Significance and Societal Importance of the Research Achievements

本研究においてはレーザ光のパルス幅・強度と、対象媒体への擾乱の大きさ、及び期待される感度の関係を、実験とシミュレーションを通じ、定量的に把握した。、測定法としてもっとも重要な事案である、正確な測定が行える適用範囲と、各範囲において達成できるスペックを明確化することができた。非侵襲で高い分解能で電界を測定できる手法であることから、放電機構の解明、放電利用機器の一層の効率化、非線形絶縁材を用いた絶縁設計技術の確立に資するものである。