内嵌圆饼空心方形银纳米结构的光学性质

Optical properties of silver hollow square embedded disk nanostructures

采用离散偶极子近似方法计算了内嵌圆饼空心方形银纳米结构的消光光谱以及其近场的电场强度分布,并进一步与空心方形纳米结构的消光光谱和表面电场做比较.结果表明,在耦合作用下内嵌圆饼空心方形银纳米结构不仅产生了新的共振模式,而且新的共振模式在传统表面增强拉曼散射的激发波长范围内,进而可以弥补由于实验上运用纳米切片法所制备的空心方形纳米结构尺寸较大导致其共振吸收峰在远红外波长范围的不足.此外,可以通过改变内嵌圆饼空心方形银纳米结构的形貌参数调节其表面等离子体共振峰的共振波长,以满足在表面增强拉曼散射、生物分子或化学分子探测上的应用.

In this paper, we calculate the extinction spectra and the distribution of electric near-field of the nanoparticles which are embedded a disk in a hollow square structure through using the discrete dipole approximation method, and compare our results with extinction spectra and the distribution of electric near-field of the single hollow square nanostructure. The research results show that a new resonant mode, which is located in the traditional excitation wavelength range of surface enhanced raman scattering, can be produced due to the coupling interaction. Then, we can use this mode to meet the shortage of the hollow square nanostructure fabricated by nanoskiving. In addition, the surface plasmon resonance peak can be tuned by changing the shape parameters of the silver nanoparticle. These results can be used in Raman scattering, molecular biological, and cheraical detection.