Black phosphorus as saturable absorber for the Q-switched Er:ZBLAN fiber laser at 2.8 {\mu}m

摘要

Black phosphorus, a newly emerged two-dimensional material, has attractedwide attention as novel photonic material. Here, multi-layer black phosphorusis successfully fabricated by liquid phase exfoliation method. By employingblack phosphorus as saturable absorber, we demonstrate a passively Q-switchedEr-doped ZBLAN fiber laser at the wavelength of 2.8 {\mu}m. The modulationdepth and saturation fluence of the black phosphorus saturable absorber aremeasured to be 15% and 9 {\mu}J/cm2, respectively. The Q-switched fiber laserdelivers a maximum average power of 485 mW with corresponding pulse energy of7.7 {\mu}J and pulse width of 1.18 {\mu}s at repetition rate of 63 kHz. To thebest of our knowledge, this is the first time to demonstrate that blackphosphorus can realize Q-switching of 2.8-{\mu}m fiber laser. Our researchresults show that black phosphorus is a promising saturable absorber formid-infrared pulsed lasers.