Research Of Optical Properties And Sensing Of Gold Nanoparticles And Thz Generation Enhanced By Gold Nanostructures

Nanoparticles and nanostructures of noble metals, especially gold andsilver, have unique optical properties which are different from bulkmaterials. External electromagnetic field will cause surface plasmonresonance of free electrons on the surface of the metal and thus bring aboutthe unique optical properties, which make metal have many applications onoptics. There have been many efforts on nanoparticles and nanostructures ofnoble metals and there are many applications based on their characteristics.Therefore, fundamental research of the properties of the metallicnanoparticles and nanostructures is very important, it will lead to betterapplications of nanoparticles and structures on other realms. For this, thefundamental optical characteristics of noble metals, surface plasmonresonance of metals and localized surface plasmon resonance ofnanoparticles are introduced and the main work of thesis involves thefollowing parts.We introduce the principle of the finite difference time domain (FDTD)method and make simulations on single gold nanosphere and nanorod tostudy the optical property and the scattering. Then we calculate the goldnanosphere pair structure and study the effect of radius and the separation’schange of the nanostructure on the localized enhancement. After that, adevice to generate THz-wave by difference frequency generation process inthe lithium niobate crystal enhance by gold nanowire arrays is designed. Weanalyze the characteristics of the device and discuss the structure parameterof the nanowire arrays. Then we offer an improvement of the device which makes the lithium niobate crystal Ti-diffused and we obtain THz output ofmWs.We also present the imaging of gold nanorods based on the condition ofinstruments of a common lab by photoluminescence and two-photoluminescence. Images of gold nanorods are obtained by different setups and their strengths and weaknesses are discussed. Thus, the proper waysfor different requirement are determined. Finally, the objective thatsuccessfully obtains the image of metallic nanoparticles and structures withvery low cost are completed. We find an easy way for researches on metalnanoparticles under lab conditions.