THERMAL EFFECTS IN OPTICAL-PHASE CONJUGATION IN C-60 AND C-70 TOLUENESOLUTIONS

We performed degenerate four-wave mixing experiments in the nanosecond time domain on C-60 and C-70 toluene solutions, using 4.5-ns pulses a t 365 nm. The results obtained suggest that a thermal mechanism is res ponsible for the long-lived component of the third-order optical nonli nearity. Thermally induced third-order susceptibilities chi(3) = 2.1 x 10(-18) m(2) V-2 and 1.6 x 10(-18) m(2) V-2 were obtained for C-60 to luene and C-70 toluene, respectively. Evidence of oscillatory acoustic modes in the nonlinear medium is presented. (C) 1997 Optical Society of America.