Research On Application Of Saturable Absorption Characteristics Of New Two-Dimensional Materials In Short-Pulse Fiber Lasers

The rapid development of ultra-fast fiber lasers is closely related to saturable absorbers?SAs?.The use of two-dimensional materials to prepare saturable absorbers for use in fiber lasers has become one of the most popular ways to achieve ultra-short pulses.New two-dimensional?2D?materials mainly include Graphene,transition metal dichalcogenides?TMDs?,black phosphorus?BP?,and topological insulators?TIs?,etc.Due to the simple preparation process,low cost,wide operating band and high damage threshold of these two-dimensional materials,they have become outstanding SAs in the field of pulsed laser applications.This paper focuses on the nonlinear saturable absorption properties of new two-dimensional materials and their applications in fiber lasers.1T-Ti Se₂,Ge Se and2H-Ta Se₂ nanosheets materials were prepared by liquid phase exfoliation?LPE?method.Using the saturable absorption characteristics of these two-dimensional materials,stable pulse operation was achieved in the fiber laser,and the experimental results were analyzed and discussed.The specific research content is as follows:?1?Research on ultrafast fiber laser based on 1T-Ti Se₂ SA.A series of characterization and optical characteristics tests were performed on 1T-Ti Se₂ nanosheets.?1?Using1T-Ti Se₂ SA to realize passively Q-switched erbium-doped?Er-doped?fiber laser.When the pump power is 400 m W,the maximum output power of the output pulse is 5.85 m W,the pulse duration is 1.31?s,and the corresponding pulse energy is 79.3 n J.It is fully proved that 1T-Ti Se₂ nanosheets have good nonlinear saturable absorption characteristics and is suitable for short pulse operation.?2?Using 1T-Ti Se₂ SA to achieve mode-locked erbium-doped fiber laser.The 1.5?m ring cavity was rebuilt to achieve stable conventional solitons?CSs?mode-locking and bound-state solitons mode-locking.In the CSs mode-locked mode,the pulse duration of the output pulse is 1.74 ps,the pulse repetition frequency is 3.23 MHz,and the maximum average output power is 2.904 m W.In the bound-state solitons mode-locked mode,two identical solitons form bound-state pulses at a time interval of 6.1 ps,and the bound-state pulses are uniformly distributed at a repetition rate of 3.23 MHz.?2?Research on passive Q-switched erbium-doped fiber laser based on Ge Se SA.A series of characterization and optical properties tests were performed on Ge Se nanosheets.Using Ge Se SA to achieve stable pulse output in erbium-doped fiber laser,which proved the nonlinear saturable absorption characteristics of Ge Se nanosheets.The repetition frequency at this time increased from 22.8 k Hz to 77.59 k Hz.When the pump power is 515m W,the maximum output power of the output pulse is 3.58 m W,the pulse duration is 1.51?s,and the corresponding pulse energy is 46.14 n J.?3?Research on passive Q-switched erbium-doped fiber laser based on 2H-Ta Se₂ SA.A series of characterization and optical characteristics tests were performed on 2H-Ta Se₂nanosheets.Using 2H-Ta Se₂ SA to achieve stable pulse output in erbium-doped fiber laser,when the pump power is 515 m W,the maximum output power of the obtained output pulse is 2.98 m W,the pulse duration is 1.53?s,and the corresponding pulse energy is 65.5 n J.For the first time,2H-Ta Se₂ nanosheets have been demonstrated to have non-linear saturable absorption characteristics and is suitable for pulsed laser applications.