椭圆截面偏心金纳米管的光学特性研究

Optical properties of elliptical gold nanotubes with a nonconcentric core

摘要:

基于时域有限差分法研究了几何尺寸、内核材料和外界环境、入射光偏振方向对椭圆截面偏心金纳米管光学性质的影响. 结果表明, 当入射光偏振方向平行截面长轴时, 随着内核偏移量的增大, 消光光谱中出现高阶峰且共振峰红移, 同时在长波长处出现一个强度增大的新峰. 新峰随偏心纳米管整体尺寸、内核折射率增大而红移且强度增大, 随外界环境折射率增大而红移但强度减小, 随短轴增大蓝移且强度减小, 其它峰的改变也各有不同. 当入射光偏振方向与截面长轴夹角增大时, 消光峰红移.

Abstract:

Based on the finite difference time domain method, the effects of geometrical parameters, refractive indices of core and embedding medium and polarization directions of incident light on the optical properties of elliptical gold nanotubes with a nonconcentric core are investigated. The results show that when the polarization direction of the incident light is parallel to the long axis of the elliptical section, with the increase of kernel offset, higher order peaks appear and red shift in the extinction spectra, moreover, a new gradually increasing peak appear in the longer wavelength region. The new peak red shifts and its intensity increases with the increases in nanotube overall size and refractive index of core material, but the intensity decreases as refractive index of embedding medium decreases, the peak blue shifts and its intensity decreases with the increase in the short axis, the other peaks change differently as well. Furthermore, with increasing the angle between the polarization direction of the incident light and the long axis, the extinction peaks red shift.