Stimulated Raman Photothermal Microscopy towards Ultrasensitive Chemical Imaging

Stimulated Raman scattering (SRS) microscopy has shown enormous potential in revealing
molecular structures, dynamics and couplings in complex systems. However, the sensitivity of SRS is
fundamentally limited to milli-molar level due to the shot noise and the small modulation depth. To
overcome this barrier, we revisit SRS from the perspective of energy deposition. The SRS process pumps
molecules to their vibrationally excited states. The thereafter relaxation heats up the surrounding and
induces refractive index changes. By probing the refractive index changes with a laser beam, we introduce
stimulated Raman photothermal (SRP) microscopy, where a >500-fold boost of modulation depth is
achieved. Versatile applications of SRP microscopy on viral particles, cells, and tissues are demonstrated.
SRP microscopy opens a way to perform vibrational spectroscopic imaging with ultrahigh sensitivity.

This dataset is the complete raw data used in the paper to support the findings.