Large third-order susceptibility and third-harmonic generation in centrosymmetric Cu(2)O crystal.

We present what we believe to be the first experimental determination of the third-order optical susceptibility chi((3)) of bulk cuprous oxide (Cu(2)O) crystals. The measured nonlinear refractive index, obtained with the Z-scan technique at 1064 nm, is n(2)=1.32x10(-10) esu, while the two-photon absorption coefficient is beta=5.