Reverse saturable absorption of C-60 in liquids irradiated by picosecond and nanosecond laser pulses

Reverse saturable absorption of C-60 dissolved in different solvents has been investigated under irradiation with 7-ns or 25-ps laser pulses at 532 nm. The results show that the solutions act as efficient power-limiting media under laser fluence of as high as 3 J/cm(2) for both picosecond and nanosecond laser pulses. The reversely saturated (clamped) level depends on the type of solvent used. It was found that the saturated level is the lowest with carbon disulfide in comparison with several other solvents. A phenomenological model is used to describe optical limiting phenomena, including the darkening effect of C-60 and the possible contribution of the solvent at high laser intensity. (C) 1996 Optical Society of America.