Study Of Visible High Absorption And Infrared High Reflection Mechanism Based On Surface Plasmon

In recent years,the preparation of low-emission infrared coatings has become a hot research topic,while maintaining the high reflectivity of thin films in far infrared band and satisfying the high absorption characteristics of thin films in visible band.Surface plasmon has special optical properties such as selective absorption of light and enhancement of local electric field.It is the basis of many metal nanoparticle structure absorbers.It can achieve large areas of absorption by metal nanoparticles perfectly at nanoscale,and has little influence on infrared band.It has good application prospects in the preparation of infrared low emission coatings.In this paper,the structure mechanism and preparation methods of metal nanoparticles/dielectrics/metals with different structures based on plasmon oscillator resonators with high absorption in visible band and high reflection in far infrared band are studied.The main contents include:A series of periodic metal nanoparticles/dielectrics/metal structures with different materials,sizes and periods are designed by COMSOL.The nanoparticles include silver cube and gold island.The visible band reflectance,far infrared band reflectance,electric field and magnetic field maps of the whole structure are calculated.Optimum design structure can be obtained by adjusting the size,material,shape,thickness of dielectric layer,period of metal particles and other parameters.The mechanism of resonance absorption enhancement and resonance peak location of periodic metal nanoparticles/dielectrics/metal structures in visible light band are studied,which mainly includes local plasmon resonance mode,cavity mode and photoelectric absorption of metal itself.Using magnetron sputtering,chemical synthesis,nanoparticle self-assembly and other methods to design the structure of the experimental preparation,and complete the preparation of thin films with different structure and thickness of dielectric layer and comparative experiments.As for test devices,we use ultraviolet/visible spectrophotometer to test the reflection spectrum in visible band,and analyze the resonance peak mechanism produced by plasma oscillator at different positions.We also use fourier infrared spectrometer to test far infrared waveband reflectance spectrum,determining the decline degree of infrared reflectance,and the results are compared with the simulation data.The results show that the visible high absorption and infrared high reflection film based on plasmon mode has significant advantages and research value.