Enhanced Optical Nonlinear Property Based On Plasmonic Metal Nanostructures

As a leading role of the modern material field,the nanomaterial is going on replacing the traditional material in the all kinds of applications.Among the many kinds of nanomaterials,the noble metal is developed into an important branch for its special physical,chemical and biological characters,and plays an important role in the modern optical imaging and communication,biological sensing and detection,the optical thermal power generation and storage for the new energy.In the optical field,the nanomaterial based on the noble metal has a special gift because of the free electronics inside,which is different from the traditional optical materials.When an incident light goes through at the interface,the electromagnetic fields will influence the electronics inside the metal and the electromagnetic resonances of these electronics with the damping force will be produced.Then the resonances of the electronics will also influence the outside electromagnetic fields.This particular interaction between the electronics and fields is called surface plasmon(SP).The SP,distributed at the surface of the metal,has the smaller wavelengths and could local the incident electric field in a small area and enhances it largely.This could provide a good application platform for the nonlinear optics.The nonlinear optics is an important branch of the optics based on the material dispersion.When the incident light is focused on a piece of the material,the nonlinear reaction will be produced with the increasing of the incident light power,such as the generation of the light at different frequency and the changing of the refractive index.As it is mentioned before,the nonlinear optics needs the strong incident electric field,which is different with the traditional optics.And the surface plasmon provides a good environment for this.So the nonlinear optics based on the SP is very popular in many scientists’research in recent years.It is different with the traditional nonlinear optics which needs the phase match condition and the accumulation in the long region.The design of it is focused on the strong enhancement of the electric field in the nano size area,which results in the harmonic generation,sum frequency generation,saturated absorption,self-focusing effect and the photoelectric modulation.In this paper,we mainly talk about the nonlinear optics from the gold nanostructures based on the SP,including the self-phase modulation and the sum frequency generation.In the first chapter of this thesis,we mainly introduce the research progress and the application background of the nonlinear optics from the gold nanostructures based on the SP.We focus on self-phase modulation based on the 2-D material and the gold nano-film and the enhancement of the second harmonic generation and sum frequency generation.In the second chapter of this thesis,we mainly introduce theory and the experiment of the nonlinear optics from the gold nanostructures based on the SP.And introduce the self-phase modulation and the experiment(called z-scan experiment),which is based on the self-phase modulation effect,and the theory&experiment of the second harmonic generation and the sum frequency generation.In the third chapter of this thesis,we mainly introduce that the self-assemble gold nanoparticle film is used to enhance the third nonlinear coefficient of the self-phase modulation.It includes:the way of chemical synthesis of the nanoparticle and the preparation of the self-assemble gold nanoparticle film,the result of the z-scan experiment,the analysis of the physic behind this enhancement effect.In the fourth chapter of this thesis,we mainly introduce the metal-dielectric-metal nanostructure,which is used to enhance the sum frequency generation.In this experiment,we use two crossed polarized pump beams to excite the nanostructure and get the enhanced sum frequency generation and the second harmonic generation signal.And analyze the physic behind it from the surface effect.In the fifth chapter of this thesis,we summarize the main work of the nonlinear optics from the gold nanostructures based on the SPP and provide perspectives to the future research works.