POLARIZATION-SENSITIVE COHERENT ANTI-STOKES RAMAN-SPECTROSCOPY

We show that by using polarization coherent anti-Stokes Raman spectroscopy, the detection sensitivity of weak Raman modes is greatly enhanced. The spectra of the real part, the imaginary part, and the absolute magnitude of the resonant nonlinear susceptibility can be separately measured. Raman modes with cross sections as low as 2×10-4 times that of the 992-cm-1 mode of benzene are detectable with less than 10-kW-peak-power lasers.