Absorptive and refractive nonlinearities by four-wave mixing for Au nanoparticles in ion-implanted silica.
We report a theoretical and experimental study on the real and imaginary part of the third-order nonlinear optical susceptibility at 532 nm and 7 ns pulse for high-purity silica samples containing Au nanoparticles prepared by ion implantation. We present a method for measuring the magnitude and sign of refractive and absorptive nonlinearities based on four-wave mixing (FWM). This method is derived from a comparison of the light intensities of incident and self-diffracted polarized waves. In the nanosecond regime the samples exhibit saturable absorption and it seems that a thermal effect is the mechanism responsible of nonlinearity of index.
Torres-Torres
C
C
Khomenko
A V
AV
Cheang-Wong
J C
JC
Rodríguez-Fernández
L
L
Crespo-Sosa
A
A
Oliver
A
A