HIGH-SPEED COHERENT RAMAN IMAGING WITH BROADBAND COHERENT ANTI-STOKES RAMAN SCATTERING MICROSPECTROSCOPY
Charles H. Camp Jr., Young J. Lee, Christopher M. Hartshorn, Evangelos G. Gatzogiannis, and Marcus T. Cicerone
Coherent Raman imaging (CRI) techniques, such as coherent anti-Stokes Raman scattering (CARS), have demonstrated superior speed and sensitivity for imaging biological samples compared to spontaneous Raman microscopy. Extending these techniques to microspectroscopy, however, has proven challenging in maintaining high-speed and spectral coverage. In this work, we demonstrate a new broadband CARS (BCARS) system that uses ultra-compressed supercontinuum pulses from a fiber laser source to provide high-sensitivity Raman excitation over a large spectral range (>4000 cm-1), covering the fingerprint through the CH- and OH-stretch regions, and a CMOS camera-equipped spectrograph to provide pixel dwell times down to 160 ms. To demonstrate these capabilities, we present multispectral images of murine brain tissue, human bone marrow stromal cells (hBMSCs), and polymer tissue scaffolds that distinguish morphological features based on molecular spectra.