Preparation And Nonlinear Optical Properties Of Low-dimensional Nano-material Composite Gel Glass

Low-dimensional nanomaterials have good nonlinear optical properties and have potential application prospects in lasers and laser protective equipment.However,at present,most of the research on nonlinear optical effects by domestic and foreign scientists is concentrated in the liquid phase matrix,which limits the practical process.In this paper,black phosphorus quantum dots(BP QDs),black phosphorus nanosheets(BP NSs)and graphdiyne oxide nanosheets(GDYO NSs)are selected as the representatives of three low dimensional nano materials.Sol-gel technology is used to doping them into organic modified silica gel glass.The morphology,structure and linear optical properties of the materials were characterized by transmission electron microscope,scanning electron microscope,atomic force electron microscope,X-ray photoelectron spectroscopy,X-ray diffraction,infrared analysis spectrum,Raman spectrum,UV-visible absorption spectrum and fluorescence emission spectrum.The nonlinear optical properties and mechanism of the composite gel glass were studied by nanosecond and picosecond Z-scanning methods.The results show that:1.Uniformly dispersed BP NSs was successfully prepared by liquid phase stripping method and introduced into silica glass by sol-gel technology.The results of Z-scan show that the saturation absorption properties(SA)of BP NSs are improved after the introduction of BP NSs into silica gel glass,and the SA is related to the doping concentration.Because the rigid silica glass matrix effectively isolates the influence of water and oxygen in the air,the nonlinear optical properties of BP NSs in the composite gel glass are greatly improved.Even after 12 months in the air,the nonlinear absorption coefficient of BP NSs can still reach 62% of the original value.The nonlinear optical effects of composite gel-glass are mainly derived from nonlinear absorption(NLA)and nonlinear refraction(NLR).2.5～10nm BP QDs was successfully prepared by liquid phase stripping and solvothermal method and introduced into silica gel glass.Energy spectrum analysis,Raman spectrum and fluorescence spectrum showed that BP QDs was successfully introduced into silica gel glass and retained its original structure.BP QDs composite gel glass exhibits saturation absorption characteristics at nanosecond and picosecond,and SA effect is enhanced compared with BP QDs liquid matrix.The saturation absorption coefficient of BP QDs composite gel glass increases with the increase of laser energy and doping concentration.3.GDYO NSs was introduced into silica glass matrix by sol-gel method to obtain composite glass with uniform doping and good transparency.Under the nanosecond laser pulse,GDYO NSs solution has an energy-related transition from saturated absorption to anti-saturated absorption.Under the picosecond laser pulse,GDYO NSs solution presents a saturation absorption effect,and with the increase of laser energy,the nonlinear absorption coefficient increases,and the saturation absorption effect increases.When GDYO NSs is introduced into solid matrix,the saturated absorption performance of GDYO NSs is improved,and the nonlinear absorption coefficient of GDYO NSs composite gel glass increases with the increase of concentration.In addition,the comparison of picosecond opening Z-scan curves of graphene(GO)and GDYO shows that the saturation absorption effect of GDYO NSs is better than that of GO in both liquid and solid phase matrix.