THz plasmonic resonances in hybrid reduced-graphene-oxide and graphene patterns for sensing applications

Abstract

Abstract:In this contribution, we e ectively combine important developments of nowadays technology: graphene based THz plasmonics, reduced-graphene-oxide (rGO) based sensors, and capability of patterning graphene materials at micro and nano scale. Surface waves in graphene were observed for the rst time only few years ago, con rming the ability of this exceptional material to support plasmons at relatively low frequencies -a few THz -due to its intrinsically huge selfinductance. On the other hand, graphene oxide, and its reduced forms, has emerged as a very interesting material for several applications, including gas sensors and biosensors. In this work, the possibility of a ne and controlled patterning of the above materials is considered as a useful degree of freedom to govern plasmon resonances and consequent electromagnetic absorption. In particular, the excitation of THz plasmons in arrays of nanoribbons, made of graphene and rGO, has been deeply investigated, in order to quantify the sensitivity to surface changes of conductivity, due to possible external perturbations. Fullwave analysis of hybrid metal-graphene-rGO is also presented and discussed. The e ects of substrate thickness and of higher di raction modes are rigorously taken into account, as a possible mean to enhance the sensing capability of the proposed device.

Recent Advances in the Development of Materials for Terahertz Metamaterial Sensing

“…[ 21–23 ] Consequently, hybrid metamaterials are attracting increasing interest from researchers because they possess the advantages of several artificial magnetic materials, which can play a key role in the TMS process. [ 24,25,86,146–156 ] For example, the hybrid metamaterials containing Au and graphene components combine the high sensitivity of Au with the dynamic tunability of graphene. [ 22,25,152 ] The excellent performance characteristics of terahertz hybrid metamaterials make them applicable in biomedical science and environmental monitoring with a possibility of further structural optimization for property enhancement.…”

“…Some of these devices are fabricated on hard substrates, while the other devices are fabricated on flexible substrates. The hard substrate materials for TMS applications include silicon, [ 1,2,5,53,67,80,83,117,147,148,151 ] gallium arsenide, [ 59,133,134,158 ] glass, [ 111,146 ] SiO 2 , [ 21,54,96–99,102,103,150 ] quartz, [ 55,90,131,140 ] AlN, [ 164 ] SiN x , [ 64 ] and sapphire. [ 144 ] They are usually characterized by the high permittivity and high resistance (such as those of silicon and gallium arsenide).…”

Terahertz range resonances of metasurface formed by double-layer grating of microsize graphene strips inside dielectric slab

“…To obtain a representation of the role of the electron relaxation time, τ , we present the same data for two values of this parameter: τ = 1 ps in figure 3 b – d and τ = 0.5 ps in figure 3 e , f . The latter value is achieved today in experimental research with CVD graphene [34], while the former value is still a matter for the future, hopefully not too distant. As one can see, the greater mobility of electrons results in sharper resonances, although their amplitudes are nearly the same in both cases.…”

“…However, the lattice-mode resonances, apparently overlooked in [7], can be even more attractive because of their drastically larger Q -factors and hence higher values of the sensor's figure-of-merit. This is equally valid for another novel sensor configuration, where a single graphene strip grating is placed on the surface of a dielectric layer backed with a continuous graphene layer [34].…”

Terahertz-range plasmon and whispering gallery mode resonances in the plane wave scattering from thin microsize dielectric disk with graphene covers

“…The resonance frequencies of these modes, as a result, are also tunable with the aid of a DC bias. The resonances on the graphene plasmon modes are actively studied today and have already found applications in the design of novel biosensors [5][6][7] and antennas [8] in the mid-infrared and THz ranges. The use of graphene, instead of the noble metals, in the design of plasmonic nanolasers is also actively discussed [9].…”