Viscosity dependence of optical limiting in carbon black suspensions.

We measure the optical limiting behavior of carbon black suspensions in various viscosity solvents by using a 10-Hz repetition rate, 532-nm, 5-ns pulsed laser. We found that, for common solvents used in the past such as water and ethanol, the limiting behavior ceases after a few laser firings and a turnover in the limiting curve appears. This can be explained by depletion of the carbon black within the focal volume.