Abstract

Over a dozen reports of optically-induced changes of up to a factor of 5 in the absorption cross-section of the C₆₀ molecule at 532 nm¹ have prompted us to investigate whether there might be a correspondingly large change in the (in-phase) polarizability of C₆₀ at the same wavelength. Unfortunately for nonlinear optical applications, we have found a negative answer: the change is less than 3% for the polarizability of C₆₀ upon excitation to either the lowest singlet or triplet state. In the course of this investigation, we have made, we believe, a more accurate determination of the absorption cross-sections σ_S and σ_T of the lowest excited singlet and triplet states of C₆₀ molecules. This is achieved with a picosecond pump-probe technique not previously applied to C₆₀. Our measurements of the polarizability changes were done with time-delayed degenerate four-wave mixing experiments. Our experiments were performed in a solution of 0.68 g/L of C₆₀ in benzene.

© 1996 Optical Society of America