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arXiv · 1903.07384

Quantitative phase imaging with molecular vibrational sensitivity

Miu Tamamitsu·Keiichiro Toda·Ryoichi Horisaki·Takuro Ideguchi
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Abstract

Quantitative phase imaging (QPI) quantifies the sample-specific optical-phase-delay enabling objective studies of optically-transparent specimens such as biological samples, but lacks chemical sensitivity limiting its application to morphology-based diagnosis. We present wide-field molecular-vibrational microscopy realized in the framework of QPI utilizing mid-infrared photothermal effect. Our technique provides mid-infrared spectroscopic performance comparable to that of a conventional infrared spectrometer in the molecular fingerprint region of 1,450 - 1,600 cm-1 and realizes wide-field molecular imaging of silica-polystyrene beads mixture over 100 μm x 100 μm area at 1 frame per second with the spatial resolution of 430 nm and 2 - 3 orders of magnitude lower fluence of ~10 pJ/μm2 compared to other high-speed label-free molecular imaging methods, reducing photodamages to the sample. With a high-energy mid-infrared pulse source, our technique could enable high-speed, label-free, simultaneous and in-situ acquisition of quantitative morphology and molecular-vibrational contrast, providing new insights for studies of optically-transparent complex dynamics.

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Miu Tamamitsu, Keiichiro Toda, Ryoichi Horisaki, Takuro Ideguchi. 2019-03-18. Quantitative phase imaging with molecular vibrational sensitivity. https://doi.org/10.1364/ol.44.003729

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