Fig. 1. The schematic of nano structure: An annular nano groove having a width of 100 nm and a depth of 100 nm is etched on the gold film having a thickness of D = 150 nm, the coaxial nanoring aperture with the inner and outer radii are r_in = 250 nm and r_out = 300 nm is located in the center of the nano groove. 纳米结构示意图. 厚度为D = 150 nm的金膜上刻蚀有宽度为100 nm、深度为100 nm的环形凹槽, 半径为R; 在凹槽的中心处有环形纳米孔, 环形纳米孔的内外半径分别为r_in = 250 nm和r_out = 300 nm, 深度与金膜的厚度相等, 形成穿孔

Fig. 2. The intensity distribution and the phase distribution of the E_x component of the incident beams (l_s = –1) at the wavelength of 800 nm: (a) The intensity distribution (l_o = 1); (b) the intensity distribution(l_o = 2); (c) the intensity distribution(l_o = 3); (d) the intensity distribution(l_o = 4); (e) the phase distribution (l_o = 1); (f) the phase distribution (l_o = 2); (g) the phase distribution (l_o = 3); (h) the phase distribution (l_o = 4). The light spot is increasing with the topological number of the orbital angular momentum 波长为800 nm时, 携带不同轨道角动量的左旋圆偏振入射光(l_s = –1)的强度分布情况及电场分量E_x的相位分布情况　(a) l_o = 1对应的强度分布; (b) l_o = 2对应的强度分布; (c) l_o = 3对应的强度分布; (d) l_o = 4对应的强度分布; (e) l_o = 1对应的相位分布; (f) l_o = 2对应的相位分布; (g) l_o = 3对应的相位分布; (h) l_o = 4对应的相位分布.随着携带的轨道角动量拓扑核数逐渐增加, 入射光光斑逐渐变大

Fig. 3. (a) The phase distribution of the component of the surface plasmon polariton when the topological number of the total angular momentum carried by the incident beam at the wavelength of 650 nm equals to 3 (l_s = –1, l_o = 4); (b) the radical propagation phase φ_r of the surface plasmon polariton(SPP) when the nanostructure is irradiated by the selected four incident beams (l_s = –1, l_o = 1, 2, 3, 4). 波长为650 nm时　(a)入射光携带有光子总角动量L = 3 (l_s = –1, l_o = 4)时, 在金膜上表面激发的涡旋表面等离极化激元中电场分量 的相位图; (b)在选定的四种左旋圆偏振的照射下, 激发的涡旋表面等离极化激元在金膜上表面的传输时的径向传播相位φ_r

Fig. 4. (a)−(d) The relation of the transmittance to wavelength of incident beams and radius of the nano groove; (e) the curves of the transmission with radius of the nano groove when wavelength equals to 650 nm; (f) the difference between transmittance of total angular momentum topological number of 3 (l_s = –1, l_o = 4)and 2 (l_s = –1, l_o = 3) (a)—(d)在选定的四种左旋圆偏振光(l_s = –1, l_o = 1, 2, 3, 4)的照射下, 透射率与环形凹槽半径和波长的变化关系; (e)波长为650 nm时, 透射率随凹槽半径的变化曲线; (f)光子总角动量为3(l_s = –1, l_o = 4)的光束透射率与光子总角动量为2(l_s = –1, l_o = 3)的光束透过率之间的差值