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-Terahertz electromagnetic fences on a graphene surface plasmon polariton platform

• Xidong Wu & 
• Xiang Guo

https://www.nature.com/articles/s41598-017-03205-x

Controlling the loss of graphene can be used in the field of transformation optics. We propose a new concept of electromagnetic fence on a monolayer graphene surface plasmon polariton platform. Using a Dot-Density-Renderer quasicrystal metasurface, we can simulate the absorption of gradient index optics structures. Numerical simulations show that the incident waves to our designed electromagnetic fence are trapped toward the central lines and quickly absorbed by the high-loss region. Two basic types of electromagnetic fence and its composite structures have been designed and analyzed, which exhibit excellent broadband absorbing performances at 8 THz–12 THz. Because of its advantages in controlling the soft-boundary effects and easy manufacturing characteristics, the proposed electromagnetic fence seems very promising for THz–frequency-transformation plasmonics applications.

Abstract-Quasi-three-dimensional post-array for propagation and focusing of a terahertz spoof surface plasmon polariton

Nozomu Koja, 

John C. Young,  

Takehito Suzuki

http://link.springer.com/article/10.1007%2Fs00339-015-9259-0

This paper presents a quasi-three-dimensional post-array designed to propagate a terahertz spoof surface plasmon polariton (terahertz spoof SPP) with confinement. A transmission line making use of a terahertz spoof SPP is a promising device in the terahertz wave band, and there are many previous reports of two-dimensional structures. Three-dimensional structures provide sophisticated designs for transmission lines propagating a terahertz spoof SPP. Eigenmode analysis is used to derive a dispersion diagram for one post with boundary conditions extracted from the full model. The propagation frequency of the terahertz spoof SPP increases with lower heights or smaller diameters, and that remains virtually unchanged for post-spacing and thickness of a substrate. The analysis of the full model confirms the confinement of a terahertz spoof SPP vertically on the post-array. The magnitude of the electric field is strong around the top and bottom and weak at approximately one-third height. The terahertz spoof SPP is confined in the space around the post-array as well as a substrate, while it is confined only on substrates in conventional two-dimensional structures. The designed post-array can control the three-dimensional focusing of a terahertz spoof SPP in an arbitrary volume of space.

Abstract-Plasmonic corrugated cylinder–cone terahertz probe

Haizi Yao and Shuncong Zhong  »View Author Affiliations

JOSA A, Vol. 31, Issue 8, pp. 1856-1860 (2014)
http://dx.doi.org/10.1364/JOSAA.31.001856

The spoof surface plasmon polariton (SPP) effect on the electromagnetic field distribution near the tip of a periodically corrugated metal cylinder–cone probe working at the terahertz regime was studied. We found that radially polarized terahertz radiation could be coupled effectively through a spoof SPP into a surface wave and propagated along the corrugated surface, resulting in more than 20× electric field enhancement near the tip of probe. Multiple resonances caused by the antenna effect were discussed in detail by finite element computation and theoretical analysis of dispersion relation for spoof SPP modes. Moreover, the key figures of merit such as the resonance frequency of the SPP can be flexibly tuned by modifying the geometry of the probe structure, making it attractive for application in an apertureless background-free terahertz near-field microscope.

© 2014 Optical Society of America