Broadly Tuning Resonant Wavelengths of Contour Bowtie Nano-Antennas Operating in the Near- and Mid-Infrared

We design a series of plasmonic bowtie antennas with broadly varying resonant wavelengths from 1.34 to 3.36 $\mu\hbox{m}$ under the same antenna footprint size. Based on the prototype of contour bowtie antennas (CBAs), we modify the geometry of CBAs with extensive resonant paths and, therefore, redshift resonances and maintain the gap enhancement factors, at least at the same level with that of the solid bowtie antenna.