New Advances in Coherent Anti-Stokes Raman Scattering (cars) Microscopy

We present three approaches for improving the sensitivity and spectral selectivity of coherent anti-Stokes Raman scattering (CARS) microscopy by reducing the non-resonant background. First, epi-detection (or backward-detection) avoids the forward scattered background signal from a bulk solvent. Second, excitation with two synchronized near IR picosecond laser beams increases the signal to background ratio. Third, polarization-sensitive detection suppresses the non-resonant background from the sample.