Figure 4
From: Metamaterial study of quasi-three-dimensional bowtie nanoantennas at visible wavelengths
(a) ~60°-tilted SEM image of microholes etched ~18 min. Experimental top-view SEM images of PS spheres (b) before and (c) after plasma etching. Experimental top-view SEM images of quasi-3D bowtie nanoantennas on the (d) low, (e) middle and (f) high regions. Magnified SEM images of quasi-3D bowtie nanoantennas on the (g) low, (h) middle and (i) high regions. The blue dashed lines and word “up” represent the magnified and higher regions, respectively.
