Enhanced nonlinear optical response of an endohedral metallofullerene through metal-to-cage charge transfer

Abstract

A new mechanism for increasing the third-order nonlinear optical susceptibility, χ(3), is described for endohedral metallofullerenes. A two to three orders of magnitude increase in the nonlinear response is reported for degenerate four-wave mixing experiments conducted with solutions of Er2@C82 (isomer III) relative to empty-cage fullerenes. A value of −8.7×10−32 esu is found for the molecular susceptibility, γxyyx, of Er2@C82 compared to previously reported values of γxxxx=3×10−34 esu and γxyyx=4×10−35 esu for C60. The results confirm the importance of the metal-to-cage charge-transfer mechanism for enhancing the nonlinear optical response in endohedral metallofullerenes.