ultra-broadband excitations of plasmonic waveguides by bowtie apertures

The plasmonic bowtie antenna constantly attracts researchers’ interests recently. in this paper, we design and demonstrate polarization sensitive and ultra-broadband excitations of plasmonic waveguides. the structure is composed of a bowtie aperture aligned near a stripe waveguide, which is fabricated on a single silver layer on top of a silica substrate. the dependence of resonance spectra on the arm length of the bowtie aperture is simulated. only when the incident polarization is parallel to the waveguide direction, the plasmonic bound modes can be correctly excited. importantly, an extremely wide spectrum bandwidth of 610 nm which covers most of the visible region from 500 nm till the near infrared light of 1 μm is achieved. our investigations will have intensive applications in next-generation plasmonic integrated chips and functional devices.