Development of a real-time trace-gas analysis method based on cavity-enhanced Raman spectroscopy

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K18983
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 34:Inorganic/coordination chemistry, analytical chemistry, and related fields
• Research Institution: Kyushu University
• Principal Investigator: Zaitsu Shin-ichi 九州大学, 工学研究院, 准教授 (60423521)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: ラマン分光法 / 共振器増強法 / ラマン散乱 / 気体分析

Outline of Final Research Achievements

In this study, we challenged to develop a state-of-the-art analysis method to selectively and rapidly detect extremely small amount of specific molecular species with high sensitivity. As a result, we found for the first time the condition for the enhancement of Raman signal efficiency in cavity-enhanced spontaneous Raman spectroscopy. This enhancement occurred when the generated Raman signal matched the longitudinal mode of the cavity and underwent a cavity-enhancement effect. We experimentally investigated the dependence of several parameters that contribute to this effect and concluded that the enhancement efficiency of the Raman signal was determined by the Raman gain instead of the Raman gain bandwidth. This finding is expected to allow us to further increase the sensitivity of molecular detection methods based on Raman spectroscopy.

Free Research Field

分析化学

Academic Significance and Societal Importance of the Research Achievements

本研究を通じて、吸収分光法を超える世界最高感度を備えたラマン分光法に基づく気体分子分析法の実現に挑戦した。本研究で発見した新しい原理により、気相混合系において、極微量(ppbレベル)分子を検出可能とする新しい分析法への道筋が得られた。これは、極微量ガス分析の分野にパラダイムシフトを引き起こすと共に、ラマン散乱を分子運動の励起方法から再発明し、100年近い歴史を有するラマン分光法に新たな風を送り込むものである。この成果は、「見えないものを見えるようにする」という科学技術の基本命題において、新しい科学技術イノベーション(社会的価値)に資するであろう。