Third order optical susceptibilities of the Cu2O thin film

By performing Z-scan method with a femtosecond laser (800 nm, 50 fs, 1 kHz), we investigated the third-order optical nonlinearities of a cuprous oxide (Cu2O) film. Single-phase Cu2O film deposited on a quartz substrate was obtained using the pulsed laser deposition technique. The structure properties, surface morphology and optical transmission spectrum were characterized by X-ray diffraction, scanning electron microscopy and double beam spectrophotometer, respectively. The Z-scan results show that the Cu2O film exhibits large nonlinear refractive index, n2 = 3 × 10− 3 cm2/GW, while the two-photon absorption coefficient, α2 = 40 cm/GW, is relatively small. It implies that the Cu2O film is a promising candidate for nonlinear photonic devices.