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

摘要

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)(velence)1.32 X 10~(-10) esu, while the two-photon absorption coefficient is (beta)(velence)5.0 cm/GW of Cu_(2)O. We also observe strong third-harmonic generation (THG) from Cu_(2)O in our detection range owing to its unique crystal and electronic structure. Considering that the first nonvanishing nonlinear term is (chi)~(3), this classical semiconductor could be utilized as a promising active THG medium.