Broadband stimulated Raman hyperspectral imaging of cells and semiconductors with synchronized fiber and solid-state...

We demonstrate broadband hyperspectral stimulated Raman scattering (SRS) microscopy covering over 2000 cm^-1, which is achieved by two tunable Stokes light sources synchronized with a pump light source. Specifically, a fiber optical parametric oscillator and a fiber laser, both equipped with automatic wavelength tuning capabilities, are employed to acquire SRS signals in the ranges of 270-2040 cm^-1 and 2800-3100 cm^-1, respectively. Using this system, we perform hyperspectral SRS imaging of live HeLa cells, covering the entire fingerprint and C-H stretching regions. Furthermore, the spectral coverage in the lower fingerprint region (<1000 cm^-1) enables SRS signal acquisition of wide bandgap semiconductors. We succeed in obtaining the SRS spectra of 4H-silicon carbide (SiC) and gallium nitride and demonstrate SRS imaging of the longitudinal optical phonon-plasmon coupled mode of 4H-SiC. We anticipate that the present method will further expand the applications of SRS in various scientific fields.