Rapid Biological and Chemical Imaging using Broadband CARS Microscopy

 

Coherent anti-Stokes Raman scattering (CARS) microscopy is a multiphoton, non-invasive bio-imaging technique using molecular vibrations as a contrast mechanism.  The comprehensiveness of CARS microscopy as a chemically sensitive imaging technique has been restricted by limited spectral bandwidth.  Recent efforts in increasing the bandwidth of CARS microscopy to nearly 300 cm-1 have not significantly developed CARS into an imaging technique which allows for high chemical sensitivity in a complex environment such as the cellular cytoplasm.  To truly facilitate CARS microscopy as a chemically sensitive technique, a significantly broader spectral coverage is required.  We report the design of a broadband CARS microscope that can be used to acquire images with a spectral width of >2500 cm-1.  In addition to high spatial resolution due to its multiphoton nature, when coupled with multivariate analysis, broadband CARS microscopy can provide chemical resolution with a high confidence level.