Rsearch On Characteristics Of SPR Absorber Based On Metal Nanoarray

In recent years,Surface Plasmon Resonance（SPR）absorbers based on metal nanoarrays have attracted great interest from researchers due to their excellent electromagnetic properties.This type of absorber can highly concentrate the optical field at the interface of the dielectric layer or the metal-dielectric layer,and achieve perfect absorption characteristics of narrowband and wideband in a specific frequency band.Due to the high integration,small size,and low cost of the absorber,Biosensing,solar cells and other fields have been widely used.Many experimental studies and theoretical calculations have shown that the resonance wavelength,bandwidth and amplitude of the structure are related to the size,shape,material and surrounding medium of the structured metal particles.Therefore,this paper has carried out a series of research work mainly on the characteristics of SPR absorbers based on metal nanoarrays.The specific content of the paper is as follows:（1）A kind of absorption device combining cylindrical and double elliptical cylinders is designed.This device is based on the principle of SPR and has a narrow-band absorption rate of98.68%in the near-infrared band for incident waves.On the basis of this structure,metal holes are used instead of metal particles,and it is observed that the performance of the hole array absorber is better than that of cylindrical and elliptical arrays.The absorption performance data is given by FDTD,and the principle of SPR is analyzed according to the electromagnetic field distribution diagram.（2）A new type of absorbing device structure with four elliptical cylinders opposite to the long axis is designed.At the same time,the absorption performance of the structure and the structural parameters（such as the long and short axis of the ellipse,the distance between the ellipses,the unit period and each layer The relationship between the thickness）is also calculated by FDTD.The structure also has the characteristics of being insensitive to incident polarization and strong absorption at wide-angle oblique incidence.Through the existing structure,it is found that the structure of the multi-layer resonant unit will make the absorption bandwidth of the structure wider and the absorption rate higher.On the basis of this structure,the single-layer titanium particles are replaced with multilayer Al₂O₃-Ti-Al₂O₃ particle arrays.It is observed that the performance of the absorber of the multilayer resonant array is better than that of the single-layer resonant layer array structure.The absorption performance data is obtained,and the principle of SPR at several wavelengths is analyzed according to the electromagnetic field distribution diagram.