INVESTIGATIONS OF OPTICAL LIMITING MECHANISMS IN CARBON PARTICLE SUSPENSIONS AND FULLERENE SOLUTIONS

Liquid suspensions of carbon act as optical limiters in the presence of high-intensity Q-switched laser pulses. The optical Limiting is a result of optical breakdown, which is initiated by absorption in the small carbon particles. We measured the total energy scattered during the breakdown process and the angular distribution of the scattered light as a function of input energy. We also compared the relative scattered energy created during limiting in the carbon suspensions with that generated in solutions of fullerenes in toluene. The ratio of scattered to absorbed energy is different for the suspensions from that for the fullerene solutions, indicating that different mechanisms dominate the limiting processes in the two media.