Near-resonance enhanced label-free stimulated Raman scattering microscopy with spatial resolution near 130 nm

摘要

High-resolution optical microscopes that can break 180 nm in spatial resolution set to conventional microscopies are much-needed tools.However,current optical microscopes have to rely on exogenous fluorescent labels to achieve high resolution in biological imaging.Herein,we report near-resonance enhanced label-free stimulated Raman scattering (SRS) microscopy with a lateral resolution near 130 nm,in which the high-resolution image contrast originates directly from a low concentration of endogenous biomolecules,with sensitivity gains of approximately 23 times.Moreover,by using a 0.3-m-long optical fiber,we developed hyperspectral SRS microscopy based on spectral focusing technology.Attributed to enhancements in spatial resolution and sensitivity,we demonstrated high-resolution imaging of three-dimensional structures in single cells and high-resolution mapping of large-scale intact mouse brain tissues in situ.By using enhanced high-resolution hyperspectral SRS,we chemically observed sphingomyelin distributed in the myelin sheath that insulates single axons.Our concept opens the door to biomedical imaging with ～130 nm resolution.