Dark modes in symmetric bulk Dirac semimetal dimers excited by cylindrical vector beams

Abstract

Dark plasmonic modes with sharp spectral resonance peak and exceptionally high quality factor makes it essential for applications in bio-chemical sensing and fluorescence enhancement. Here, we investigate the mid-infrared spectral responses of bulk Dirac semimetal (BDS) dimers under focused azimuthally polarized and radially polarized cylindrical vector beams (CVB). Through numerical simulations, we obtained direct excitation of dark modes and revealed how the beams manipulate the dipole hybridization to produce these modes. By tuning Fermi energy of BDS, the resonant wavelength of the dark modes can be further adjusted. Our results may find the application of CVB in plasmonic sensing.

Plasmon-induced transparency in borophene waveguide with strong absorption inhibition at critical-coupled state

“…PIT based on MIM waveguide structures can be divided into two types. Near-field coupled PIT is formed by the direct coupling of bright and dark modes, 13,18,19) while phase coupled PIT is usually realized by constructive or destructive interference between evanescent fields of two modes without direct coupling. 20,21) PIT of specified metallic nanostructures is implemented at a fixed wavelength, which restricts their applications in the active system.…”