The excited-state absorption and third-order optical nonlinearity from 1-dodecanethiol protected gold nanoparticles: Application for optical limiting

Few studies have been carried out on near-IR picosecond optical nonlinearity and excited-state absorption of stable gold nanoparticles. In this article, the near-IR picosecond optical nonlinearity from 1-dodecanethiol protected gold nanoparticles (Nano-1) was investigated by using Z-scan technique. The incident laser is a Q-switched/mode-locked Nd:YAG pulses laser with a duration of 35 ps at 1064 nm. The experimental results indicate that Nano-1 solution in tetrahydrofuran (THF) shows high excited-state absorption and a negative third-order refraction index. Due to this high excited-state absorption, a highly effective optical limiting behavior was observed for Nano-1 in THF solution in solution with a low optical limiting threshold.