Research Of The Passively Q-switched Performance Of Two Dimensional Metal-organic Frameworks

In recent years,with the development of pulse laser technology,people putforward higher requirement in nonlinear optical material.2-dimensional materials(2D-materials)represented by graphene have attracted extensive attention in society.The saturable absorber made of this kind of material has the advantages of compact structure,small space occupation,wide absorption waveband,short response time,low optical loss and high efficiency,solve many problems of traditional Q-Switching/mode lock components,such as complex manufacturing,high production cost,the working band is relatively narrow,and many other restrictions.Thus,the 2D-materials has a broad application prospect in the field of solid-state lasers.So far,great achievements have been made in the field of laser and nonlinear optics in such 2D-materials like transition metal disulfides(TMDs),topological insulator(TIs),graphene and black phosphorus,but as a result of the limitation of its own nature,or the flaws in the preparation process,the traditional 2D-materials can’t meet the demand in many occasions.Therefore,the exploration of novel,stable and excellent two-dimensional materials have become the focus of current researchers.This paper focuses on the metal-organic frameworks(MOFs)2D nanosheets and elemental 2D-material tellurene,γ-graphyne as the research object,made them into saturable absorbers and applied in Nd:YAG solid-state lasers,and realize the stable Q-switching laser pulse output in multiple wavelength.The main research contents are as follows:1.The layered y-graphyne nanosheets were prepared successful and evenly dispersed in sapphire substrate.The properties of the material were characterized by using scanning electron microscope,atomic force microscopy and Raman spectroscopy,and the linear transmittance of 2D y-graphyne nanosheets was measured by uv-visible-infrared spectrophotometer.The relation between the nonlinear transmittance of the sample and the incident power density has been studied,and the saturation intensity and modulation depth were obtained.With Nd:YAG crystal as the gain medium,inserted the as-prepared 2D layered graphyne nanosheets into the plane-concave cavity to realize the 1.06 μm solid-state passively Q-switched laser operation,which finally proves the good saturation absorption characteristics of 2D layered y-graphyne nanosheets in the infrared waveband.2.The mercuated graphdiyne organometallic nanosheets(MGONs)that prepared by bottom-up method have been studied,analyzed the structure of MGONs,and the saturable absorption properties of two 2D MGONs HgL1 and HgL2 were reasearched by open aperture Z-scan at different wavelengths.3.Using saturation absorption properties of HgL1 and HgL2,were realized 1.06μm solid-state passively Q-switched laser;studied the passively Q-swicthed laser performance for two kinds of nanosheets inserted in Nd:YAG solid-state lasers under different conditions,including annealing process,sample ligand concentration and different coupling output transmittance.4.The tellurene nanosheets were successfully prepared by LPE method,and the material properties were characterized in many aspects by means of scanning electron microscope,atomic force microscope,transmission electron microscope,and Raman spectroscopy.The linear/nonlinear transmission properties of 2D tellurene nanosheets was studied.The parameters such as saturation intensity,modulation depth and damage threshold were obtained.On this basis,a flat-concave laser resonator was used to achieve the solid-state passive Q-switched laser operation with the wavelengths of 1.06 and 1.3 μm,which proved that tellurene had excellent saturable absorption performance in the near-infrared wavebandAfter systematic study,y-graphyne has a high damage threshold and well energy storage effect,but the modulation depth is low,and the Q-switching performance is not ideal.The MGONs has high damage threshold,wide modulation depth and high saturation intensity,and can precisely control the thickness by adjusting ligand concentration,but the pulse width and peak power are not as good as tellurene.Tellurene has a low pump threshold and better modulation effect,which can exhibit a better modulation effect in low pump threshold Q-switching,but the damage threshold and saturation intensity are lower,and the sample is easily damaged.Generally speaking,several materials have shown their advantages in some aspects,but they also have their own defects.