Gold nanoparticles PVA thin film as Q-switcher in neodymium doped fiber laser cavity

A gold nanoparticle-based saturable absorber (SA) was successfully employed in Neodymium-doped fiber laser (NDFL) cavity for pulse generation via a Q-switching mechanism for the first time. The SA device was made by mixing the gold nanoparticles into PVA solution before being dried to form a thin film was included into the NDFL cavity, which was optimized to obtain Q-switched pulses centered at wavelength of 1089 nm. The pulse rate of the laser rose from 37.37 to 49.60 kHz while the pulse width fell from 4.82 to 3.84 $\mu$ s as the 808 nm pump laser was raised from 98 to 144 mW. At the highest input pump power of 144 mW, the maximum output power and pulse energy was achieved at 0.52 mW and 10.48 nJ, respectively. The developed Q-switched laser has numerous applications including, material micromachining, communication, sensing, etc.