Nonlinear absorption properties in gold nanoparticles for passively Q-switched laser and optical limiting applications

Regarded as an essential transition metal, gold holds significant research value in the academic realm. In this work, gold nanoparticles were prepared by a combination of magnetron sputtering and liquid-phase exfoliation. The nonlinear optical properties of gold nanoparticles had been systematically investigated by utilizing the open aperture Z-scan method with both nanosecond and picosecond laser sources, which were rarely involved in previous studies. Based on the saturation absorption properties of gold nanoparticles, we prepared a gold saturable absorber and successfully applied it in generating passively Q-switched pulses in Pr:YLF crystal laser and Nd:YAG crystal laser, respectively. And we also analyzed its optical limiting applications. Our systematic study confirms that gold nanoparticles are suitable as candidates for saturable absorbers and optical limiting materials.