TIME-RESOLVED DEGENERATE 4-WAVE-MIXING IN THIN-FILMS OF C-60 AND C-70 USING FEMTOSECOND OPTICAL PULSES

Thin films of pure C60 and C70 have been studied by time-resolved degenerate four-wave mixing using femtosecond optical pulses with a wavelength of 633 nm. Large optical nonlinearities were measured for both materials, with chi-(3) values almost-equal-to 10(-10) esu. The degenerate four-wave mixing signal was monitored as a function of the relative arrival times for the excitation pulses. Along with a long-lived (almost-equal-to 100 ps) component to the four-wave mixing decay, response dynamics occurring on both femtosecond and picosecond time scales were observed for both materials.