The Research On Optical Second Harmonic Generation In Low-dimensional Transition Metal Dichalcogenides

The discovery of graphene and its excellent properties has grasped people's eyes and led people to two-dimensional graphene-based materials,however the narrow band gap restricts the potential applications of graphene.As low-dimensional transition metal dichalcogenide has a similar structure to graphene and a bigger band gap,it is seems as the material of next generation electronics.From 2010 there is an exponential growth of paper focus on the transition metal dichalcogenide,and it is one of the most intensely studied areas of solid state physics and technology.Second harmonic is the most significant phenomenon in nonlinear optics.Through the study of the second harmonic,we can further promote our understanding of the optical properties of transition metal dichalcogenide,and thus promote the application of this material.The main work of this paper is listed as below:(a)As second harmonic generation has a relationship of the symmetry of the crystal structure,the dependency of the number of crystal layers is studied;(b)The relationship between the fileds of second harmonic and the fundamental laser is studied.What's more,for varied wavelength of fundamental laser,the relationship between the fluorescence spectrum and second harmonic generation is also studied;(c)Based on the property that second harmonic generation is sensitive to the crystal structure,the crystal direction is measured by the polarized beam.And the continuous change of crystal structure is measured based on the optical properties of low-dimensional materials,both include fluorescence spectrum and second harmonic generation.