Ultrafast third-order nonlinear optical response of C84, C84–D2 (IV) and C84–D2d (II)

The third-order nonlinear optical response of fullerene C84 (isomeric mixture as obtained from fullerenic soot) and its most abundant isomers C84–D2 (IV) and C84–D2d (II) dissolved in toluene were investigated by the Optical-Kerr-effect technique using 100 fs laser pulses at 830 nm. The second-order hyperpolarizabilities of C84, D2 and D2d were determined to be (0.93 ± 0.22) × 10−30, (0.94 ± 0.22) × 10−30 and (6.4 ± 1.2) × 10−30 esu, respectively. The enhancement of the nonlinearity of the D2d isomer as compared with the D2d one is discussed.