Analyzing broadband tunable metamaterial absorbers by using the symmetry model

Abstract

In this paper, a broadband tunable absorber based on bulk Dirac semimetal (BDS) in the far-infrared regime is studied. By optimizing the Femi energy and geometric size, the structure can achieve absorption levels greater than 90% in the 8.11-13.94 THz range, with a total thickness of 5.1 µm. Further, the bandwidth of this proposed absorber can be dynamically controlled by changing the Femi energy of the BDS instead of geometry. Meanwhile, the polarization and oblique incident angles in the TE and TM electromagnetic waves are also investigated. Finally, a new symmetry model is adopted to analyze the absorption mechanism, which is the innovation of this paper. This research result may provide potential applications for all types of optical photovoltaic devices and tunable biological chemistry sensors.

Review of Broadband Metamaterial Absorbers: From Principles, Design Strategies, and Tunable Properties to Functional Applications

“…There is a BDS‐based BMA in the LIR region, [ 269 ] which can achieve >90% absorption in the 8.11–13.94 THz range. Its bandwidth can be dynamically controlled by varying the Fermi energy of the BDS, which may provide potential applications for various types of optical photovoltaic devices and tunable biochemical sensors.…”

“…This is also the main reason why we have witnessed a large number of different patterned top resonators being designed and proposed, such as rectangular patches, [256,257] square rings, [258,259] circular discs, [260,261] and split rings. [262,263] Unlike most MAs using precious metals (such as Au, Ag) as the preferred materials of the top layer, some more popular emerging materials have been introduced and integrated into the MAs, such as graphene, [264][265][266] bulk Dirac semimetals (BDS), [267][268][269] VO 2 , [93,112,270] which often bring unexpected absorption effects, while enriching the design of MAs, it can also expand the application prospects of MAs.…”

“…This preset goal could be easily realized by introducing electrically tunable active materials into the structures of BMAs. These active materials mainly include graphene, [456,500,501] BDS, [268][269]457,502] liquid crystals, [104,453,503] etc. Currently, many references have been reported by applying bias voltages into the active materials of graphene and BDS to vary their Fermi energy to realize the electrically tunable BMAs.…”

Side-Polish Plastic Optical Fiber Based SPR Sensor for Refractive Index and Liquid-Level Sensing

“…where θ c = sin −1 (n cl /n co ) is the critical angle of total reflection, n co and n cl are the RI of the POF core and cladding, and P(θ) = (n 2 co sinθcosθ)/(1 − n 2 co cos 2 θ) 2 is the modal power corresponding to the angle of incidence θ. R P is the total reflectivity [29], N = L /(2D•tanθ) is the total amount of light reflection in the sensing region, where D is the remaining diameter of the fiber, and θ is the angle of incidence at the fiber core-gold film interface. L is the effective length of the sensor immersed in the measured liquid.…”

“…Surface plasmon resonance (SPR) is a physical optical phenomenon based on the interaction between incident light and free electrons in the metal layer [1,2]. As early as 1968, Otto et al proposed an SPR excitation device with a prism as an optically coupled structure [3], and subsequently, Kretschmann and Raether further improved the Otto structure, and the metal film was directly plated on the prism surface, which can effectively excite the SPR effect [4].…”