Abstract-Terahertz surface plasmon polariton resonances and microparticle sensing in bulk Dirac semimetal with spatially perturbed geometries

 

Tony Mathew Blessan and N. Yogesh

https://www.osapublishing.org/josab/abstract.cfm?uri=josab-38-8-2261

Bulk Dirac semimetals (BDSs) are a three-dimensional counterpart of graphene and exhibit rich plasmonic response at terahertz (THz) frequencies. In this work, we investigate THz surface plasmon polariton (SPP) resonances in BDS systems with spatially perturbed geometries using Kretschmann–Raether and Otto configurations. A THz SPP conversion efficiency of around 91% is witnessed in a straight BDS slab with the Otto configuration. The sustainment of THz SPP resonances for microbending and macrobending BDS geometries reveals the confinement capabilities of the BDS system as a potential sensing element. For example, microparticle sensing is demonstrated numerically based on THz SPP resonance in a parabolically perturbed BDS system. A reflection amplitude change of more than 75% is observed for microplastic-like spherical particles stuck on the surface of a parabolic BDS in comparison with an empty parabolic BDS configuration. We anticipate that the demonstrated THz SPP resonances and sensing in BDS systems may enable plasmonic devices for environmental monitoring and biological sensing.

© 2021 Optical Society of America

Abstract-Controllable broadband asymmetric transmission of terahertz wave based on Dirac semimetals

Linlin Dai, Yuping Zhang, John F. O’Hara, and Huiyun Zhang

 (a) PCR of linearly polarized wave, (b) the current densities in the top and bottom layers of the x-polarized wave at 1.389 THz and 1.668 THz, respectively.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-27-24-35784

We present a dynamic metamaterial based on Dirac semimetals and capable of realizing broadband and tunable asymmetric transmission in the terahertz region. The Dirac semimetal resonators have a chiral structure patterned with double-T resonators that results in partial polarization conversion of waves incident upon the material, leading to asymmetric transmission across a wide frequency range. We show how the gradual shift of the semimetal Fermi energy permits a method of control over the asymmetric total transmission.

© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Dirac semimetals based tunable narrowband absorber at terahertz frequencies

Gui-Dong Liu, Xiang Zhai, Hai-Yu Meng, Qi Lin, Yu Huang, Chu-Jun Zhao, and Ling-Ling Wang

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-9-11471

In this paper, a bulk Dirac semimetals (BDSs) based tunable narrowband absorber at terahertz frequencies is proposed and it has the attractive property of being polarization-independent at normal incidence because of its 90° rotational symmetry. Numerical results show that the absorption bandwidth is about 1.469e-2 THz and the total quality factor Q, defined as Q = f0/Δf, reaches about 94.6, which can be attributed to the low power loss of the guided mode resonance in the dielectric layer. The simulation results are analyzed with coupled mode theory. Interestingly, on the premise of maintaining the absorbance at a level greater than 0.95, the absorption frequency can be tuned from 1.381 to 1.395 THz by varying the Fermi energy of BDSs from 50 to 80 meV. Our results may also provide potential applications in optical filter and bio-chemical sensing.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement