中文摘要：

采用离散偶极子近似方法（DDA）研究了两种不同形状的金纳米环结构的消光光谱及其近电场分布,研究了等离子体消光峰的红移、蓝移现象及消光系数与结构参数之间的关系,并与盘状的金纳米结构进行了比较.在等离子体共振峰波长入射时,金纳米环结构比金纳米盘结构产生更大的局域增强电场分布,横截面为圆形的金纳米环结构比横截面为矩形的结构具有更大的局域增强电场分布,更适合作为表面增强拉曼散射的衬底.

英文摘要：

The extinction spectrum and the electric field distribution of gold nanoring structure have been calculated and compared with those of gold nanoplate structure by using the discrete dipole approximation method.It is found that the plasmon resonance peaks can have a red-shift or blue-shift when the radius size and the shape of the nanoring change.The gold nanoring with square cross section has a largest extinction coefficient.At the main plasmon peak,the nanoring with circlar cross section has much stronger electric field and larger electric field distribution,which can serves as the surface enhanced Raman scattering substrate for biological and chemical detections.