ORIGINS OF BULK 2ND-HARMONIC GENERATION IN C(60) THIN-FILMS

Electric field induced second harmonic generation in C60 thin films wa s investigated. The measured bulk second order nonlinear optical respo nse of C60 was identified as arising from nonlinear polarization momen ts of higher order than the electric dipole moment. The third order no nlinear optical susceptibility chi(3) (-2omega; omega, omega, 0) was d etermined from these measurements to be 3.6 x 10(-11) esu for the fund amental wavelength of 1.06 mum, in good agreement with published data.