Ultrafast fiber laser based on HfSe2 saturable absorber.

We demonstrate the HfSe₂ saturable absorber (SA) for the generation of ultrafast pulse laser. The HfSe₂ SA device is fabricated by integrating HfSe₂ nanosheets (NSs) with a microfiber. The material and optical characteristics of HfSe₂ NSs show their high quality. The nonlinear optical absorption of HfSe₂ SA is measured with a modulation depth of 5.8%. Stable soliton mode-locked laser based on HfSe₂ SA is realized at the central wavelength of 1561.43 nm with pulse duration of 297 fs and the maximum pulse energy of 2.68 nJ. Our soliton fiber laser has a maximum output power of 48.5 mW with a high slope efficiency of 12.8%, which indicate that HfSe₂ is a good candidate of SA for high efficient ultrashort pulses generation. [ABSTRACT FROM AUTHOR]