  By using nanosecond laser pulses at 532-nm wavelength, we have studied the
nonlinear optical properties of composites which consist of mono-functional
1,2-dihydro-1,2-methanofullerene[60]-61-carboxylic acid (FCA) and
poly(styrene-co-4-vinylpyridine). The optical limiting performance of FCA
itself is poorer than that of its parent C60, while FCA incorporated with
polystyrene shows better optical limiting responses, with the limiting
threshold reduced by about 35%. In addition, the FCA gives slightly stronger
photoluminescence emission than that of both C60 and FCA/polymer composites.
The possible sources for the improvement in the optical limiting are discussed.
