Chemically Selective Imaging of Subcellular Structure in Human Hepatocytes with Coherent Anti-Stokes Raman Scattering (CARS) Near-Field Scanning Optical Microscopy (NSOM)

We demonstrate the combination of coherent anti-Stoke Raman scattering (CARS) with near-field scanning optical microscopy (NSOM) for chemically selective imaging via intrinsic vibrational resonances with spatial resolution below the diffraction limit. Femtosecond, near-IR pulses are used to produce CARS signals from human hepatocytes, and by tuning the CARS signal to be resonant with C−H stretching frequencies, image contrast is observed with an optical spatial resolution of ∼128 nm.