Origin and time dependence of higher-order nonlinearities in metal nanocomposites

The higher-order nonlinear optical response of a composite medium having metal nanoparticles is usually attributed to that originating from the third-order nonlinearity of the metal. In this article, the time dependence of hot-electron contribution to the third-, fifth-, and seventh-order nonlinear absorption coefficients of the composite medium has been studied. By comparing the results of the calculation with that of the experiments, it has been shown that the higher-order nonlinearities originating from the hot electrons of metal do contribute to the measured higher-order nonlinear absorption coefficients of the composite material. (C) 2011 Optical Society of America