Time-resolved stimulated Raman scattering microscopy for robust quantitative chemical measurements in tissue

Quantitative measurements of a small amount of chemicals in label-free tissue imaging by conventional SRS microscopy remain challenging because of background signals. We present a time-resolved, phase-modulated (PM) SRS microscopy method with increased signal contrast. In addition to removing background signals generated via amplitude modulation, PM-SRS can reduce intrinsic tissue background signals by temporally separating the excitation and detection processes. Furthermore, polarization artifacts in tissues can also be removed by rapidly modulating the relative delay between the pump and probe pulses. This new technology enables robust quantitative measurements in tissue and extends the potential of SRS imaging in biomedical applications.