Fig. 1: Experimental design and workflow.

a Illustration of gastroscopy and taking fresh biopsy for direct SRS imaging. b Properties of femto-SRS and pico-SRS, in terms of pulse chirping, spectral resolution, and conversion from single femto-SRS image to a pair of pico-SRS images using deep U-Net. c Multi-chemical imaging of gastric tissue composed of lipid (green), protein (blue) and collagen fibers (red) from converted femto-SRS and SHG channels, and color-coded to SRH. DM dichroic mirror, GM galvo mirror, PD photodiode, SRS stimulated Raman scattering, SHG second-harmonic generation, SRH stimulated Raman histology. Scale bars: 50 µm. Source data are provided in the Source data file.