Design and optimization of bowtie nanoantenna for electromagnetic field enhancement

Designing a plasmonic structure having high near field enhancement of incident field, large hot spot area, wideband resonance, and multiple resonance peaks are the key elements to obtain large electromagnetic field enhancement factor for various biosensors like surface-enhanced Raman scattering and Spasers. In this paper, we have proposed three different configurations of the bowtie nanoantenna represented as Single Bowtie Structure, Double Bowtie Structure (DBS), and Triple Bowtie Structure (TBS). Numerical simulations are performed with the characteristics of Nanoantenna and the analysis of the influence of the size parameter of the antennas along with the optimization of this parameter is performed to achieve the maximum near field enhancement. The result shows that TBS delivers the highest enhancement factor with a triple resonance peak. Whereas, in the second portion, the demonstrated results show the influence of the size on the enhancement of the incident field which further indicates, that as the size reduces the enhancement decreases. Furthermore, variations in the gap are simulated with four types having simple bowtie structure, reduced symmetry of DBS, reduced symmetry of TBS, and double reduced symmetry of TBS. The results significantly showed that type 4 configuration covers a wider wavelength with enhanced near electromagnetic field.

Automated summary

This paper proposed three different configurations of bowtie nanoantennas, optimized the size parameters to achieve maximum near field enhancement, and found that the Triple Bowtie Structure (TBS) delivers the highest enhancement factor with a triple resonance peak. Moreover, the study showed that the enhancement decreases as the antenna size reduces.