A new, transparent, metal-free absorber, based on the use of multilayer graphene/dielectric laminates (GLs), is proposed for applications in the low-terahertz frequency range. The designed absorber has a total thickness of around 70 µm and consists of a front matching dielectric layer followed by a GL, a dielectric spacer and a back GL. The laminates are periodic structures constituted of graphene sheets separated by 50-nm-thick polyethylene terephthalate (PET) interlayers, while the matching layer and the spacer are one-quarter-wavelength thick and made of PET. The GLs are modeled as homogeneous-equivalent single layers (ESLs) characterized by their sheet resistances Rs. An innovative analytical method is proposed in order to select Rs values optimizing the electromagnetic wave absorption either in low-gigahertz or low-terahertz frequency range. The frequency spectra of the absorption, reflection and transmission coefficients are computed in the range up to 4 THz by using different values of Rs. Then, realistic Rs values of chemically doped graphene monolayers over PET substrates are considered. The designed absorbers are characterized by an absorption coefficient with a peak value of about 0.8 at the first resonant frequency of 1.1 THz, and a 1.4 THz bandwidth centered at 1.5 THz with reflection coefficient below - 10 dB. Moreover, the optical transmittance of the proposed absorbers are computed by means of the optical matrix theory and it is found to be greater than 86% in all the visible ranges.

Low-Terahertz Transparent Graphene-Based Absorber / D'Aloia, ALESSANDRO GIUSEPPE; D'Amore, Marcello; Sarto, Maria Sabrina. - In: NANOMATERIALS. - ISSN 2079-4991. - 10:5(2020), pp. 1-17. [10.3390/nano10050843]

Low-Terahertz Transparent Graphene-Based Absorber

Alessandro Giuseppe D’Aloia
Primo
;
Marcello D’Amore
Secondo
;
Maria Sabrina Sarto
Ultimo
2020

Abstract

A new, transparent, metal-free absorber, based on the use of multilayer graphene/dielectric laminates (GLs), is proposed for applications in the low-terahertz frequency range. The designed absorber has a total thickness of around 70 µm and consists of a front matching dielectric layer followed by a GL, a dielectric spacer and a back GL. The laminates are periodic structures constituted of graphene sheets separated by 50-nm-thick polyethylene terephthalate (PET) interlayers, while the matching layer and the spacer are one-quarter-wavelength thick and made of PET. The GLs are modeled as homogeneous-equivalent single layers (ESLs) characterized by their sheet resistances Rs. An innovative analytical method is proposed in order to select Rs values optimizing the electromagnetic wave absorption either in low-gigahertz or low-terahertz frequency range. The frequency spectra of the absorption, reflection and transmission coefficients are computed in the range up to 4 THz by using different values of Rs. Then, realistic Rs values of chemically doped graphene monolayers over PET substrates are considered. The designed absorbers are characterized by an absorption coefficient with a peak value of about 0.8 at the first resonant frequency of 1.1 THz, and a 1.4 THz bandwidth centered at 1.5 THz with reflection coefficient below - 10 dB. Moreover, the optical transmittance of the proposed absorbers are computed by means of the optical matrix theory and it is found to be greater than 86% in all the visible ranges.
2020
low-terahertz transparent absorber; graphene-polyethylene terephthalate laminate; laminate effective medium model; transmission line approach; absorption; reflection and transmission performance up to 4 THz; optical transmittance in the visible range
01 Pubblicazione su rivista::01a Articolo in rivista
Low-Terahertz Transparent Graphene-Based Absorber / D'Aloia, ALESSANDRO GIUSEPPE; D'Amore, Marcello; Sarto, Maria Sabrina. - In: NANOMATERIALS. - ISSN 2079-4991. - 10:5(2020), pp. 1-17. [10.3390/nano10050843]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1414259
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