Femtosecond optical nonlinearity of metallic indium across the solid liquid transition.

A very strong (~10(-8) esu) femtosecond cubic nonlinearity in metallic indium that increased sharply in magnitude as the temperature approached the melting point was observed.

Cubic optical nonlinearity of free electrons in bulk gold.

A fast (Tau(response) <90 fs) free-electron spin-f lipping frequency-degenerate nonlinearity with a signif icant value of|chi((3))(xxyy)(omega,omega,omega,-omega)chi((3))(xxyy)(omega,omega,omega,-omega)|~10(-)(8)esu has been observed in bulk gold at 1260 nm by use of a new pump-probe polarization-sensitive technique.