CUBIC OPTICAL NONLINEARITIES OF METALS IN THE VICINITY OF THE MELTING-POINT

We report the first study of frequency degenerate cubic optical nonlin earities in bulk metals across the melting point. Using pump-probe ref lectivity and precise Dump-probe polarimetry a strong femtosecond elec tronic nonlinearity (chi((3)) approximate to 10(-8) esu) has been obse rved in indium. The effective nonlinearity sharply increases when the temperature approaches the melting point. We also report the results o f a study on the nonlinearity of nickel films and discuss the effect o f an interface with glass on the magnitude and sign of the nonlinearit y.