Near-field detection of Goos-Hanchen shift for highly sensitive single molecule sensing

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K18958
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 28:Nano/micro science and related fields
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: HAYAZAW NORIHIKO 国立研究開発法人理化学研究所, 開拓研究本部, 専任研究員 (90392076)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: グースヘンシェンシフト / 近接場光学 / 表面プラズモン

Outline of Final Research Achievements

In this project, we will integrate near-field detection for the first time in the world in a refractive index sensor based on Angular Goos-Hanchen Shift (A-GHS), a new analysis method, and improve the sensitivity expressed in molar concentration. We have developed a new method with the aim of innovatively improving this and making it possible to express the sensitivity at the number-of-molecules level. In FY2022, we upgraded the previously developed A-GHS system at room temperature and atmospheric pressure so that it can measure in a liquid environment with biosensor applications in mind, and develop a cell for a liquid environment using PDMS. In FY2023, we designed and developed a method to detect weak near-field components from extremely strong background light with high efficiency by lock-in detection of the near-field scattered light of the A-GHS beam.

Free Research Field

近接場光学

Academic Significance and Societal Importance of the Research Achievements

センサー感度は「ナノモル」や「ピコモル」等のモル濃度で議論されることが多い。高感度を示すよう聞こえるが、分子数で表記すると、10^11~10^14個という途方もない数である。本課題では、角度グースヘンシェンシフト (Angular Goos-Hanchen Shift: A-GHS）に基づく屈折率センサーにおいて、近接場検出を世界で初めて融合させ、モル濃度で表現されていた感度を分子数レベルの感度表記で可能とする。究極的に１分子感度の達成を目指しており、本分析手法は、昨今のSARS-CoV-2といったウイルス検出需要に応えるだけでなく、あらゆる分子種に対して適応できる汎用性の高い手法となり得る。