Fig. 1. Schematics and optical spectra of (a), (b) spontaneous Raman scattering and (c), (d) CRS. Adapted and modified from Ref. [3].

Fig. 2. Typical schematic of SRS microscope. PD, photodiode. Adapted and modified from Ref. [3].

Fig. 3. Multicolor SRS methods based on (a) wavelength scanning, (b) spectral focusing, (c) wavelength-multiplexing, and (d) modulation-frequency multiplexing. Adapted from Ref. [3].

Fig. 4. Examples of SRS imaging reported by the author and co-workers. (a) Hyperspectral SRS image of two types of polymer beads [polystyrene and poly(methyl methacrylate) (PMMA)]. (b) SRS spectra taken at the arrows shown in (a)^[12]. (c) Hyperspectral SRS image of acetaminophen-overdosed mouse liver tissue^[30]. (d), (e) Uptake of boron cluster compound cholesterol by HeLa cells for (d) 2 h and (e) 4 h^[39]. (f) Multicolor SRS imaging flow cytometry of Euglena gracilis cells cultured in different conditions. Green, chlorophyll; red, paramylon; blue, lipid^[40].