采用离散偶极近似(Discrete Dipole Approximation,DDA)方法考察核壳比和外界介质折射率对ITO/Au、CdS/Au、Nb-Sn/Au纳米核壳粒子表面等离子体共振消光特性的影响,并利用杂化理论对其物理本质解释。仿真结果表明,ITO/Au和CdS/Au纳米核壳的ω－模式对应的共振峰峰位随核壳比的增加逐渐红移,而Nb-Sn/Au纳米核壳对应的共振峰峰位随核壳比的增加逐渐蓝移；ω+模式对应的四极共振峰峰位随核壳比的增大缓慢蓝移；集中在金壳两极点的振荡电荷对核壳球模式和腔模式的耦合作用以及电场分布有显著影响；相同尺寸纳米核壳的消光能力由强到弱依次是ITO/Au、Nb-Sn/Au、CdS/Au。

The influence of core-shell ratio and refractive index of the surrounding medium on the surface plasmon resonant characteristic of ITO/Au,CdS/Au,Nb-Sn/Au are investigated by the discrete dipole approximation based on the plasmon hybridization theory.The numerical results indicate that the ω－mode corresponding to dipole resonance peak of ITO/Au and CdS/Au is red-shifted with the increase of core-shell ratio,whereas the peak of the Nb-Sn/Au is blue-shifted.The ω+mode corresponding to quadrupole resonance peak is blue-shifted with the increase of core-shell ratio.Meanwhile,the oscillating surface charges always concentrate close to the poles of the metal surface,which results in the local electric field distribution and affects the coupling between inner and outer surface plasmon mode.The level of extinction properties of gold nanoshell with the same size from the highest to the lowest is ITO/Au、Nb-Sn/Au、CdS/Au.