Tuning of Graphene-Based Optical Devices Operating in the Near-Infrared

Vorobev, Artem S.; Bianco, Giuseppe Valerio; Bruno, Giovanni; D’Orazio, A.; О’Faolain, L.; Grande, Marco Actis

doi:10.3390/app11188367

Cited by 14 publications

(9 citation statements)

References 73 publications

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“…The wavelength-dependent absorption A(λ) was inferred from the wavelength-dependent transmittance T(λ) and reflectance R(λ) (A(λ) = 1 − R(λ) − T(λ)) [ 71 , 72 ], by using the Wave Optics Module of Comsol Multiphysics software. Graphene optical properties were simulated by a wavelength-dependent complex refractive index

[ 73 , 74 ], where the single-layer graphene permittivity was [ 75 , 76 , 77 ]:

being

(2.5) [ 78 , 79 ], t G (0.35 nm) [ 80 , 81 ], and σ ( ω ) the intrinsic contribution to the graphene relative permittivity, the thickness of single layer graphene and the graphene optical conductivity, respectively.…”

Section: Resultsmentioning

confidence: 99%

Towards Perfect Absorption of Single Layer CVD Graphene in an Optical Resonant Cavity: Challenges and Experimental Achievements

et al. 2022

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Graphene is emerging as a promising material for the integration in the most common Si platform, capable to convey some of its unique properties to fabricate novel photonic and optoelectronic devices. For many real functions and devices however, graphene absorption is too low and must be enhanced. Among strategies, the use of an optical resonant cavity was recently proposed, and graphene absorption enhancement was demonstrated, both, by theoretical and experimental studies. This paper summarizes our recent progress in graphene absorption enhancement by means of Si/SiO2-based Fabry–Perot filters fabricated by radiofrequency sputtering. Simulations and experimental achievements carried out during more than two years of investigations are reported here, detailing the technical expedients that were necessary to increase the single layer CVD graphene absorption first to 39% and then up to 84%. Graphene absorption increased when an asymmetric Fabry–Perot filter was applied rather than a symmetric one, and a further absorption increase was obtained when graphene was embedded in a reflective rather than a transmissive Fabry–Perot filter. Moreover, the effect of the incident angle of the electromagnetic radiation and of the polarization of the light was investigated in the case of the optimized reflective Fabry–Perot filter. Experimental challenges and precautions to avoid evaporation or sputtering induced damage on the graphene layers are described as well, disclosing some experimental procedures that may help other researchers to embed graphene inside PVD grown materials with minimal alterations.

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[ 73 , 74 ], where the single-layer graphene permittivity was [ 75 , 76 , 77 ]:

being

Section: Resultsmentioning

confidence: 99%

Towards Perfect Absorption of Single Layer CVD Graphene in an Optical Resonant Cavity: Challenges and Experimental Achievements

et al. 2022

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“…• Tunable surface conductivity of 2D graphene sheet can be achieved by shifting of the Fermi energy level or chemical potential from the Dirac point [13] (at the intersection of the conduction band and the valence band).…”

Section: A Materials Characteristics Of Graphenementioning

confidence: 99%

GITz: Graphene-assisted IRS Design for THz Communication

Sharma¹,

Agarwal²,

Mishra³

et al. 2022

Preprint

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Graphene-based intelligent reflecting surface (GIRS) has been proved to provide a promising propagation environment to enhance the quality of high frequency terahertz (THz) wireless communication. In this paper, we characterize GIRS for THz communication (GITz) using material specific parameters of graphene to tune the reflection of the incident wave at IRS. In particular, we propose a GITz design model considering the incident signal frequency material level parameters like conductivity, Fermi-level, patch width to control the reflection amplitude (RA) at the communication receiver. We have obtained the closed-form expression of RA for an accurate design and characterization of GIRS, which is incomplete in the existing research due to the inclusion of only phase-shift. The numerical simulation results demonstrate the effectiveness of the proposed characterization by providing key insights.

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“…In the case of the graphene layer, the conductive surface has opted for analysis of construction, and the graphene layer's thickness is 1nm in the model [38,39]. For extraction of the desired conductivity concerning graphene by Equation (2), we consider the temperature and relaxation time as 300 K and 1 ps, respectively [28,40]. Considering the appropriate data related to temperature and relaxation time is essential for the structure design because these parameters can change the conductivity and optical properties of the graphene sheet.…”

Section: System Designmentioning

confidence: 99%

“…On this basis, the optical response in the absorption band can be engineered through structures that are configured with graphene [26]. Recent studies illustrate a particular attraction in the design of absorbing devices based on a single graphene layer and investigations of design challenges in the near-infrared and visible ranges [27,28]. For microwave range, the graphene layer is also interestingly used to design an optically tunable absorber [29] and switchable radar absorbing surfaces [30].…”

Section: Introductionmentioning

confidence: 99%

Electrically Tunable Perfect Terahertz Absorber Using Embedded Combline Graphene Layer

et al. 2021

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Graphene is a powerful 2-D matter with the capability of extraordinary transparency, and tunable conductivity is employed in emerging optoelectronics devices. In this article, the design of an electrically tunable graphene-based perfect terahertz absorber is proposed and evaluated numerically. The introduced structure is composed of two graphene layers with a sharp absorption peak in the terahertz band. These graphene layers are combline and stripline separated by the insulator substrate. The position of the absorption peak is tunable on the absorption band by means of manipulation in geometric parameters of the combline graphene layer. Furthermore, the intensity and frequency of the absorption peak can be flexibly modulated by varying Fermi potential of the combline graphene layer, which can be controlled through external DC voltages without the need of changing the geometry of the structure. It is shown that the absorption band can be tuned in the bandwidth from 5 to 15 in terahertz. The findings of this paper can promote a new perspective in designing perfect ribbon absorbers based on graphene properties that can be utilized for future photodetectors, solar cells, and thermal sensors with an absorption intensity above 2 × 105(nm2) with narrow absorption bandwidth of 0.112 THz.

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Tuning of Graphene-Based Optical Devices Operating in the Near-Infrared

Cited by 14 publications

References 73 publications

Towards Perfect Absorption of Single Layer CVD Graphene in an Optical Resonant Cavity: Challenges and Experimental Achievements

Towards Perfect Absorption of Single Layer CVD Graphene in an Optical Resonant Cavity: Challenges and Experimental Achievements

GITz: Graphene-assisted IRS Design for THz Communication

Electrically Tunable Perfect Terahertz Absorber Using Embedded Combline Graphene Layer

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