The Effect Of Doping On Nonlinear Optical Properties Of TiS₂ Nanomaterials

As an important branch of modern optics,nonlinear optics develops rapidly and has been applied in practice.Nonlinear optics investigates the interaction of laser and matter.With the development of nonlinear optics,there have been a lot of relevant applications,such as laser Q-switched,two-photon imaging,laser modulation and so on.Different practical applications require materials with different nonlinear optical properties.For example,laser Q-switching technology requires materials with saturated absorption characteristics,while laser limiting requires materials with reverse saturated absorption characteristics.In the present variety of materials,one material has only one corresponding nonlinear absorption property,which limits its applications.In order to broaden the application range of various materials and explore the influence of various doping on the nonlinear optical properties of materials,this thesis explores the influence of doping of two different materials on the nonlinear optical properties of TiS₂.TiS₂is one of a transition metal sulfide materials(TMDCs),which has been widely investigated in thermoelectricity,photocatalysis and optical limiting.In this thesis,the effects of doping on the nonlinear optical properties of TiS₂have been investigated and the main research contents are as follows:In this thesis,the nano TiS₂was prepared by liquid phase exfoliate method,antimony(Sb)was doped into TiS₂by solid state reaction method.And then Mo S₂was synthesized by hydrothermal method.Finally,Mo S₂was doped into TiS₂by ultrasonic dispersion method.The prepared materials were characterized by scanning electron microscope,transmission electron microscope,Raman spectrum,etc.The prepared materials were evenly dispersed in polymethyl methacrylate(PMMA)to prepare organic glass.The open-aperture z-scan technique was used to measure the nonlinear optical properties of those kinds of PMMA.The results showed that TiS₂/PMMA exhibited a reverse saturation absorption and Mo S₂/PMMA exhibited a saturation absorption.When Mo S₂doped into TiS₂,the absorption of(Mo S₂/TiS₂)/PMMA is saturated absorption at low energy,and the transition from saturated absorption to reverse saturated absorption occurs with the increase of energy.When Sb is doped into TiS₂,the nonlinear optical properties of the obtained samples are tested by open-aperture Z-scan technique,and the result shows that(Sb/TiS₂)/PMMA exhibits saturated absorption.While TiS₂/PMMA exhibited a reverse saturation absorption,that's because doping of Sb will lead to the increase of the band gap of TiS₂,so(Sb/TiS₂)/PMMA shows saturated absorption.In this thesis,the effects of metal and metal compound doping on the nonlinear optical properties of TiS₂are investigated,which provides some ideas for searching new nonlinear optical materials.