Passively Q-Switched Erbium-Doped Fiber Laser Based on HfSe2 Saturable Absorber

We report a passively Q-switched Er-doped fiber laser based on a new type of two-dimensional material HfSe2 saturable absorber HfSe2 flake is prepared by the mechanical exfoliation method and inserted into the erbium-doped fiber laser cavity to achieve a stable Q-switched laser pulse output When the pump power is 140 mW a stable Q-switched pulse is obtained by rotating the polarization controler whose stable output has a center wavelength of 1532 3 nm and a 3 dB spectral line width of 0 68 nm When the pump power increases from 140 mW to 360 mW the repetition rate of the pulse output increases from 42 3 kHz to 88 2 kHz and the pulse duration changes from 3 3 μs to 1 8 μs The experimental results show that the maximum output power of the fiber laser is 6 1 mW and the single pulse energy is 68 5 nJ at the maximum pump power