Laser ablation of GaAs in liquids: structural, optical, and nonlinear optical characteristics of colloidal solutions

We investigated the optical, structural, and nonlinear optical properties of GaAs nanoparticles prepared by laser ablation in various liquids at the wavelengths of 795 nm and 1,054 nm. The slow-thermal-effect-induced self-defocusing processes were dominating both in the cases of high pulse repetition rate and nanosecond pulses. The two-photon absorption was observed in these colloidal solutions in the case of low pulse repetition rate of picosecond and femtosecond radiation. The nonlinear susceptibility of GaAs nanoparticles ablated in water was measured to be 2 x 10(-9) esu.