Extended Data Fig. 3: Acquisition speed comparison between SuperB-SRS and spontaneous Raman.

Same sample (that is, the mixture of DMSO and D₆-DMSO with a 1:1 volume ratio) was used. Spontaneous Raman was recorded with a commercial confocal spontaneous Raman spectrometer (LabRAM Odyssey, Horiba). ~14-mW/µm² intensity of 532-nm CW laser was used for spontaneous Raman excitation. To achieve a comparable spectral resolution to that of SuperB-SRS, 3 times grating rotation is required to cover the spectral bandwidth shown above. Pixel dwell time of spontaneous Raman is set to 1 s, so the whole spectral acquisition time for spontaneous Raman is more than 3 s. SuperB-SRS is excited by ~29 mW/µm² overall pump and Stokes intensity (that is, 14.8-mW Stokes power and 8.5-mW pump power focused by 1.2 N.A. objective). Spectral acquisition time for SuperB-SRS is 8 ms (that is, the time for one round of time delay scanning). Note that the excitation efficiency of SuperB-SRS over the whole spectral band is not homogenous. SNRs of Raman modes at the center of the excitation band (that is, the mode at 1,420 cm⁻¹, etc.) for SuperB-SRS is 7.4 times higher than that of spontaneous Raman. However, SNRs of Raman modes at the excitation band edges (that is, those modes near 500 cm⁻¹) are smaller than that of the spontaneous Raman. The SNRs were calculated as the ratio of the Raman peak amplitudes to the standard deviation of the spectral baseline between 2400 cm⁻¹ and 2500 cm⁻¹.