Nonlinear properties of silver nanoparticles explored by a femtosecond Z-scan technique

Abstract

In this report we present results of linear and nonlinear optical properties of colloidal material consisting of triangle silver nanoparticles in distilled water. The nonlinear optical properties of the material were investigated by a Z-scan technique using femtosecond laser pulses with tunable wavelength. Nanoparticle suspension showed distinct spectra with absorption lines, emerging due to the plasmonic properties of the silver nanoparticles. Surface plasmon resonance peak change over a wide range of wavelengths from 400 to almost 1100 nm was observed when the size of silver nanoparticles varied from 20 to 150 nm. In the samples different nonlinear effects such as saturable absorption, two photon absorption and self-focusing were observed when the femtosecond pulse intensity was changed from 1 up to 100 GW/cm²