Pulsed laser deposition of Cu:Al₂O₃ nanocrystal thin films with high third-order optical susceptibility

Nanocomposite films comprising metal Cu nanocrystals embedded in an Al₂O₃ matrix were deposited by alternating pulsed laser ablation from metallic Cu and ceramic Al₂O₃ targets. The films were grown in vacuum on glass substrates held at room temperature. The as-grown films contain 4 nm Cu nanocrystals in an amorphous Al₂O₃ matrix, with a total thickness of 190 nm. The films show a substantial third-order susceptibility with an electronic nonlinear refractive index of (2.93±1.08)∙10^-10 cm² W^-1 and a nonlinear saturation of -(2.34±0.18)∙10^-5 cm W^-1. © 1997 American Institute of Physics.