Nanocomposite films comprising metal Cu nanocrystals embedded in anAl2O3matrix were deposited by alternating pulsed laser ablation from metallic Cu and ceramicAl2O3targets. The films were grown in vacuum on glass substrates held at room temperature. The as-grown films contain 4 nm Cu nanocrystals in an amorphousAl2O3matrix, 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−1and a nonlinear saturation of−(2.34±0.18)⋅10−5 cm W−1.©1997 American Institute of Physics.