We report observation of reverse saturable absorption in C-60 toluene
solution for 10 ns duration laser pulses in the wavelength region 710-
740 nm, for which the photon energy is less than the energy of the low
est excited singlet state. The observed nonlinear absorption appears t
o be due to excitation of molecules to the more absorbing lowest tripl
et state by direct absorption from the ground state. Our results imply
that a C-60 based optical limiter can operate over a broad spectral r
ange extending into the near-infrared. (C) 1997 American Institute of
Physics.