Simultaneous dual-channel stimulated Raman scattering microscopy demultiplexed at distinct modulation frequencies.

To increase the information per pixel in stimulated Raman scattering (SRS) microscopy as well as to correct from artifacts, it is valuable to acquire images at two different Raman shifts. We present a three-color SRS approach acquiring two perfectly registered SRS images where both pump beams are modulated at distinct frequencies while demodulating the Stokes beam. Our implementation uses two optical parametric oscillators that can be tuned to an almost arbitrary energy difference of Raman shifts, allowing investigation of fingerprint resonances simultaneously to CH-stretch vibrations.