Saturated Stimulated-Raman-Scattering Microscopy for Far-Field Superresolution Vibrational Imaging

Stimulated Raman-scattering (SRS) microscopy has emerged as a powerful tool for quantitative vibrational imaging of live tissues and cells with biochemical specificity, but the spatial resolution of SRS microscopy is still diffraction limited. We present work on saturated stimulated-Raman-scattering (SSRS) microscopy to break the diffraction limit for far-field super-resolution imaging in biological systems. A virtual sinusoidal modulation (VSM) method is also proposed for retrieval of super-resolution SSRS images. We show an experimental implementation of SSRS microscopy for enhancing the spatial resolution of SRS imaging in samples (e.g., plant cells, live HeLa cells) with a spectral focusing hyperspectral SRS system. With saturation occurring in coherent Raman processes under a certain level of excitation powers, it is anticipated that the SSRS technique has the ability to become an appealing tool for label-free far-field super-resolution SRS imaging in biological and biomedical systems.