Photonic Time-Stretch Spectroscopy for Multiplex Stimulated Raman Scattering

Stimulated Raman scattering spectroscopy enables label-free molecular identification, but its broadband implementation is technically challenging. We experimentally demonstrate a novel approach to multiplex stimulated Raman scattering based on photonic time stretch. A telecom fiber stretches the broadband femtosecond Stokes pulse after the sample to approximate to 15ns, mapping its spectrum in time. The signal is sampled through a fast oscilloscope, providing single-shot spectra at 80-kHz rate. We demonstrate high sensitivity in detecting the Raman vibrational modes of various samples over the entire high-frequency C-H stretching region. Our results pave the way to high-speed broadband vibrational imaging for materials science and biophotonics.