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采用基于有限元的数值模拟方法,建立微晶硅衬底上单个金属纳米颗粒与光相互作用的三维(3D)模型,分别计算不同半径的Ag、Al、Au和Cu球状纳米颗粒的散射截面、吸收截面、散射效率及耦合效率。结果表明:随着金属纳米球半径R的增大,表面等离激元偶极共振峰发生红移且展宽,同时颗粒的归一化吸收截面快速下降;在中长波段(500~1100 nm),颗粒的散射效率随R的增大而增大,但耦合效率则呈现单调下降趋势。在相同尺寸的Ag、Al、Au和Cu颗粒中,Au和Cu的吸收截面较大,当R=50 nm时,Au和Cu颗粒的吸收截面甚至大于其散射截面,二者在中短波段(300~550 nm)的散射效率明显偏低。另外,金属纳米颗粒的耦合效率对颗粒成分变化不敏感。
The three-dimensional (3D) model of the interaction between the single metal nanoparticles and the light on the microcrystalline silicon substrate is established by using the finite element method based on the numerical simulation. The scattering cross sections of the spherical nanoparticles with different radii of Ag, Al, Au and Cu are calculated, Absorption cross section, scattering efficiency and coupling efficiency. The results show that the dipole formant of surface plasmon polarizes redshift and broadens with the radius R of the metal nanosphere increasing, and the normalized absorption cross section of the particles declines rapidly. In the mid-long band (500-1100 nm) , The scattering efficiency of particles increases with the increase of R, but the coupling efficiency decreases monotonously. In the same size of Ag, Al, Au and Cu particles, the absorption cross section of Au and Cu is larger. At R = 50 nm, the absorption cross section of Au and Cu particles is even larger than that of the scattering cross section. 300 ~ 550 nm) the scattering efficiency is obviously low. In addition, the coupling efficiency of metal nanoparticles is not sensitive to changes in particle composition.