Laser ablation–induced synthesis and nonlinear optical characterization of titanium and cobalt nanoparticles

The studies of third-order nonlinear optical processes (nonlinear saturable absorption, reverse saturable absorption, two-photon absorption, and nonlinear refraction) in the titanium and cobalt nanoparticles synthesized by laser ablation of bulk materials in deionized water, toluene, and ethylene glycol are reported. The nanoparticle suspensions are systematically characterized by absorption spectroscopy, scanning electron microscopy, and Z-scan technique using 800 nm and 400 nm, 60 fs pulses as well as 355 nm, 6 ns pulses. The concurrence of different nonlinear absorption processes in nanoparticle-containing suspensions is discussed. We also demonstrate the optical limiting of these nanoparticles in water using the 800 nm, 60 fs pulses.