利用时域有限差分法研究了Au纳米天线对GaSb纳米线的消光增强.通过分析不同形状Au纳米阵列的电场特性和光学特性, 发现三角形为最优结构, 并具有高强度共振吸收峰和高的电场增强倍数.分别对三角形尺寸和纳米线的间距进行调节, 结果表明：随着尺寸由70 nm增加到210 nm, 消光峰位从783 nm单调增加到1 638 nm, 峰位强度和电场增强倍数逐渐增加, 尺寸为210 nm时的增强倍数为70 nm时的6倍; 随着间距由80 nm增加到130 nm, 消光峰位从1 655 nm减小到1 460 nm, 峰位强度和电场增强倍数略微减小.因此可通过先调节间距再调节尺寸的方法来设计Au纳米天线结构.

Extinction enhancement of GaSb nanowire because of Au nano antenna is studied based on finite difference time domain method. The electric field property and optical property of Au nano antenna array with different shapes are analyzed, it is found that triangular is the best structure, which possesses the resonant absorption peak with high intensity and the electric field with high enhancement factor. Then, the engineering of size and gap with nanowire of triangular structure is performed. Adjusting the triangular size and the gap of nanowire respectively, the results show that the corresponding extinction peak increases from 783 nm to 1638 nm monotonously with the size increasing from 70 nm to 210 nm, and the intensity and enhancement factor of electric field are enhanced. The size of 200 nm is six times the enhancement factor of 70 nm; Increasing the gap from 80 nm to 130 nm, the corresponding extinction peak decreases from 1655 nm to 1460 nm, with lightly weaken intensity and enhancement factor of electric field. So the optimal approach of tuning the size after the determined gap is appeared for the design of Au nano antenna structure.