Coherent Raman microspectroscopy with signal saturation for super resolution label-free imaging

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20505
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0402:Nano/micro science, applied condensed matter physics, applied physics and engineering, and related fields
• Research Institution: Kyushu University
• Principal Investigator: Oketani Ryosuke 九州大学, 理学研究院, 助教 (00908890)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 光学顕微鏡 / 超解像観察 / ラベルフリー / コヒーレントラマン / 分光イメージング / CARS

Outline of Final Research Achievements

We aimed to develop a super resolution microscopy using coherent anti-stokes Raman scattering and its saturation, which allows us to specify the object to be observed inside the sample after observation. The developed system includes CARS spectroscopic imaging part and measurement system of signal saturation. Measured CARS spectra showed some peak defects, which is presumably due to chromatic aberration in high numerical aperture measurement. We developed a correction method to the chromatic aberration and succeeded in obtaining broadband spectra without any peak defects. We also measured the excitation intensity dependence of the CARS spectrum and found that the saturation of the CARS signal depends on the molecular vibration mode. These results can be a basis achieving label-free super-resolution microspectroscopy.

Free Research Field

光工学

Academic Significance and Societal Importance of the Research Achievements

白色光を用いたCARS分光顕微鏡において、信号飽和の励起が可能であることを示した。また、CARS信号の飽和特性が分子振動モードによって異なることを発見した。この成果は、観察後に試料内部の観察対象を指定できる超解像観察法の可能にするための基盤技術となりうる。また、色収差解決のために開発した補正方法は、他の非線形光学顕微鏡にも応用できる可能性がある。色収差によってこれまで達成できなかった、近赤外域の白色光の利用が顕微鏡開発で進むことが期待される。