Temperature Dependence of the Resonant and Nonresonant CARS Signals

We have studied the temperature dependence of resonant and nonresonant CARS signals in benzene, in toluene, and in n-alcohol mixtures. A cryostat was constructed to allow cooling of flowing liquids. In nonpolar solvents, the nonresonant background signal does not seem to depend on temperature, while in n-alcohol mixtures an enhancement of the nonlinear CARS signal is observed. Lowering temperature in these solutions enhances detectability of weak impurity lines in the resonant CARS spectrum.