Large third-order nonlinear optical properties of C70 fullerene in the infrared regime

Abstract

The nonlinear third-order optical susceptibility of C70 in a toluene solution is measured for the first time by the method of degenerate four-wave mixing using 10 ns laser pulses at 1.06 μm. The third-order susceptibility X in (3) is 5.6×10−12 esu for a C70 toluene solution at a concentration of 0.476 g/l. The correspondent magnitude of the hyperpolarizability γ1111 of the C70 molecule is 1.2×10−30 esu which is in a good agreement with the prediction given by the model of a free electron in a spherical box.