Development of of trace moisture meter using an optical resonant cavity with self-resonating mechanism

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K14120
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Optical engineering, Photon science
• Research Institution: Tohoku University
• Principal Investigator: Yuuki Uesugi 東北大学, 多元物質科学研究所, 助教 (60780682)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 光共振器 / 吸収分光 / ファイバーレーザー / レーザー発振器

Outline of Final Research Achievements

In this study, single-longitudinal-mode and mode-locked feedback-free cavities (FFCs) were developed to investigate their applicability to cavity enhanced absorption spectroscopy. With a relatively low finesse cavity, a single-frequency laser was stored in the cavity by means of the FFC operating in single-longitudinal-mode operation for the first time. We was that the system could laser-oscillate at only two specific wavelengths, suggesting that the realized laser-oscillation mode depends on a longitudinal mode of a cavity-outer optical path, which has not concerned so far. On the other hand, it was found that the feasibility of applying the scheme of the FFC to optical combs spectroscopy may be still difficult due to technical challenges on the development of mode-locked FFCs.

Free Research Field

光・量子ビーム物理

Academic Significance and Societal Importance of the Research Achievements

光共振器は高感度の気体中分子計測を実現可能な光学装置であり，超高真空を用いる科学研究や最先端の半導体製造プロセス，環境計測における大気二酸化炭素同位体の測定など，我々の生活に直結する先端技術に利用することができる．本研究では，FFCの手法を用いることで，計測応用に有利な単一波長のレーザーを光共振器に安定に蓄積できることを初めて実証した．この技術を発展させることで，従来では環境雑下での取り扱いが難しかった光共振器による吸収分光計測装置を，産業現場や環境計測のためのアウトフィールドでも安定に利用することが可能になると期待される．