| Because of its excellent chemical,physical,and nonlinear optical properties,the new two-dimensional?2D?semiconductor materials have attracted great attention of many scholars in the fields of detectors,optical devices and semiconductor integrated circuits.Preparation of more excellent optical devices has been the focus of research in laser research.With the emergence of single-layer graphene materials,other graphene-like new 2D materials?represenyed by Mo S2?have gradually entered the field of vision.many optical researchers have realized ultra-fast pulsed laser operations based on new2D semiconductor materials.In this paper,we mainly study the preparation,characterization of various saturable absorbers?SAs??graphene,molybdenum disulfide and graphene/Mo S2 heterojunction?and their application in solid-state lasers.The details are as follows:?1?The Mo S2 nanosheets was prepared by liquid-phase exfoliation and mixed with anhydrous ethanol,then spin-coated it on graphene which grown via plasma enhanced chemical vapor deposition?PE-CVD?,finally the graphene/Mo S2 heterojunction SA was formed by heating and drying.At the same time,the plasma enhanced chemical vapor deposition method and liquid-phase exfoliation were used for the preparation of SAs of graphene and Mo S2.Characterization and analysis of three different saturable absorbers through Raman,transmission and SEM characterization techniques,the measured modulation depths were 7.1%,7.8%and 15.01%,respectively.The characterization results show that the heterojunction saturable absorber has more excellent optical characteristics.?2?Researched and independently built of the 1064 nm all-solid-state pulsed laser with a cavity length of 3 cm and realized passively Q-switched operations based on graphene,Mo S2 and graphene/Mo S2 SAs.When the absorbed pump power was 6.56 W,the graphene/Mo S2Q-switched laser generates a stable laser pulse with a pulse width of 180 ns and a corresponding repetition frequency of 640 k Hz.Compared with single graphene?320 ns,980 k Hz?and single Mo S2?280 ns,630 k Hz?,its saturated absorption characteristics are greatly enhanced.?3?In order to further confirm the outstanding saturated absorption characteristics of the heterojunction,the doubly Q-switched Nd:YVO4 laser based on the graphene and Mo S2 SAs was added and realized.Compared with the single material,its saturable absorption properties is stronger,and compared with the heterojunction material,its saturable absorption properties is worse.These results open up a possibility of actively regulating the saturable absorption properties of SAs by constructing heterojunctions with 2D materials. |
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