Investigation of the observation mechanism of optical transition states of organic molecules by near-field optical microscopy with force detection

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H04662
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 30:Applied physics and engineering and related fields
• Research Institution: Osaka University
• Principal Investigator: Sugawara Yasuhiro 大阪大学, 大学院工学研究科, 教授 (40206404)
• Co-Investigator(Kenkyū-buntansha): 李 艶君 大阪大学, 大学院工学研究科, 准教授 (50379137)
• Project Period (FY): 2021-04-05 – 2024-03-31
• Keywords: 光誘起力顕微鏡

Outline of Final Research Achievements

Photoinduced polarization patterns for copper phthalocyanine molecules were successfully measured with high resolution. For linearly polarized incident light, the photoinduced force increased outside the copper phthalocyanine molecule. In order to measure chirality with high sensitivity, a light irradiation system in which rightward and leftward circular polarizations are alternately switched was realized. The material surface is irradiated with light that modulates the circular polarization, and the modulation component that appears in the frequency shift of the cantilever is detected by a lock-in amplifier, enabling the measurement of chirality. Furthermore, the photoinduced force was increased inside the copper phthalocyanine molecule for circularly polarized incident light.

Free Research Field

走査型プローブ顕微鏡

Academic Significance and Societal Importance of the Research Achievements

光が誘起する分極には電子励起状態の情報が含まれ、光と物質との相互作用において中心的役割を持つ物理量である。しかし、これまで原子スケールでこれを直接観察した例はない。本研究では、励起状態・非励起状態における単一分子の光誘起分極パターンを原子分解能で観察し、その画像化機構を解明するという、これまで誰も成し得なかった究極の目標に挑戦した。したがって、本研究は、光と物質との相互作用について、これまでの固定概念の見直しを迫り、新たな現象や機能を探索・解明する研究と位置づけられる。