Stimulated Raman scattering (SRS) microscopy has emerged as a powerful tool for quantitative vibrational imaging of live cells and tissue with biochemical specificity, but the spatial resolution of SRS microscopy is still diffraction limited.  In this talk, I will present our very recent work on saturated stimulated Raman scattering (SSRS) microscopy to break the diffraction limit for the first time for far-field super-resolution vibrational imaging in biological systems. We have established a generic semi-classical model on SSRS processes to identify the parameters of ps/fs pump and Stokes beams required for SSRS imaging. I will discuss about a virtual sinusoidal modulation method for retrieval of super-resolution SSRS image. The first experimental implementations of SSRS microscopy for enhancing the spatial resolution of SRS imaging in biosamples are also presented by using a spectral focusing hyperspectral SRS system developed.  With the saturation occurring in coherent Raman processes under a certain level of excitation power, we expect that SSRS technique has ability of becoming an appealing quantitative imaging tool for label-free super-resolution vibrational imaging in biological and biomedical systems.

Bio：Dr Zhiwei Huang is Associate Professor with tenure in Department of Biomedical Engineering (BME), Faculty of Engineering at the National University of Singapore (NUS). He is the Head of Optical Bioimaging Lab at BME/NUS, and a world-renowned expert in biomedical optics and imaging. His major research areas are in the fields of biomedical optics, microscopy, Raman spectroscopy and imaging, particularly centering on the development of super-resolution microscopy and nonlinear optical microscopy imaging techniques (e.g., coherent Raman scattering microscopy and multiphoton microscopy) and their applications in biomolecular imaging, as well as the development of novel fiber-optic endoscopic imaging and spectroscopy, enabling early diagnosis and detection of epithelial precancer and cancer. He has published over 150 peer-reviewed journal papers and delivered over 80 keynote/invited talks worldwide. He has filed over 25 US patents with 10 being licensed for commercialization. He won many international awards related to novel Raman spectroscopy and imaging techniques. His IMDX technique invented was ranked No.1 among the top 10 medical devices listed in Medica, Germany. He is the node leader in Singapore in Biophotonics4Life (BP4L) Worldwide Consortium, and also a senior member of SPIE-the International Society for Optics and Photonics.