Multilayer graphene: ion gel amplitude modulator for terahertz frequency range

2020 ◽  
Author(s):  
Petr Demchenko ◽  
Aleksey Rezvykh ◽  
Ineta Grikalaite ◽  
Alexander Grebenchukov ◽  
Anna Baldycheva ◽  
...  
Keyword(s):  
Multilayer Graphene ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Amplitude Modulator ◽  
Ion Gel

scholarly journals Low-Terahertz Transparent Graphene-Based Absorber

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 843 ◽  
Author(s):  
Alessandro Giuseppe D’Aloia ◽  
Marcello D’Amore ◽  
Maria Sabrina Sarto
Keyword(s):  
Matrix Theory ◽  
Periodic Structures ◽  
Optical Transmittance ◽  
Multilayer Graphene ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Frequency Spectra ◽  
Quarter Wavelength ◽  
Doped Graphene

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.

FORM BIREFRINGENT STRUCTURES MATCHING TO FREE SPACE IN THE TERAHERTZ FREQUENCY RANGE

2015 ◽  
Vol 74 (19) ◽  
pp. 1767-1776 ◽  
Author(s):  
V. I. Bezborodov ◽  
O.S. Kosiak ◽  
Ye. M. Kuleshov ◽  
V. V. Yachin
Keyword(s):  
Free Space ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range

HIGH FREQUENCY OHMIC LOSSES IN TERAHERTZ FREQUENCY RANGE CW KLYNOTRONS

2017 ◽  
Vol 76 (10) ◽  
pp. 929-940 ◽  
Author(s):  
Yu. S. Kovshov ◽  
S. S. Ponomarenko ◽  
S. A. Kishko ◽  
A. A. Likhachev ◽  
S. A. Vlasenko ◽  
...  
Keyword(s):  
High Frequency ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Ohmic Losses

Active modulation of refractive index by stress in the terahertz frequency range

2013 ◽  
Vol 52 (25) ◽  
pp. 6364 ◽  
Author(s):  
Lin’an Li ◽  
Wei Song ◽  
Zhiyong Wang ◽  
Shibin Wang ◽  
Mingxia He ◽  
...  
Keyword(s):  
Refractive Index ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range

scholarly journals Photothermal, Photoelectric, and Photothermoelectric Effects in Bi-Sb Thin Films in the Terahertz Frequency Range at Room Temperature

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 76
Author(s):  
Mikhail K. Khodzitsky ◽  
Petr S. Demchenko ◽  
Dmitry V. Zykov ◽  
Anton D. Zaitsev ◽  
Elena S. Makarova ◽  
...  
Keyword(s):  
Thin Films ◽  
Terahertz Radiation ◽  
Room Temperature ◽  
Voltage Drop ◽  
Radiation Detection ◽  
Radiation Detectors ◽  
Thz Radiation ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range

The terahertz frequency range is promising for solving various practically important problems. However, for the terahertz technology development, there is still a problem with the lack of affordable and effective terahertz devices. One of the main tasks is to search for new materials with high sensitivity to terahertz radiation at room temperature. Bi1−xSbx thin films with various Sb concentrations seem to be suitable for such conditions. In this paper, the terahertz radiation influence onto the properties of thermoelectric Bi1−xSbx 200 nm films was investigated for the first time. The films were obtained by means of thermal evaporation in vacuum. They were affected by terahertz radiation at the frequency of 0.14 terahertz (THz) in the presence of thermal gradient, electric field or without these influences. The temporal dependencies of photoconductivity, temperature difference and voltage drop were measured. The obtained data demonstrate the possibility for practical use of Bi1−xSbx thin films for THz radiation detection. The results of our work promote the usage of these thermoelectric materials, as well as THz radiation detectors based on them, in various areas of modern THz photonics.

scholarly journals Terahertz Technologies and Its Applications

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 268
Author(s):  
Victor Pacheco-Peña
Keyword(s):  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range

The terahertz frequency range (0 [...]

scholarly journals Electrical tunability of terahertz nonlinearity in graphene

2021 ◽  
Vol 7 (15) ◽  
pp. eabf9809
Author(s):  
Sergey Kovalev ◽  
Hassan A. Hafez ◽  
Klaas-Jan Tielrooij ◽  
Jan-Christoph Deinert ◽  
Igor Ilyakov ◽  
...  
Keyword(s):  
Electric Fields ◽  
Quantitative Agreement ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Single Cycle ◽  
Terahertz Frequency Range ◽  
Third Harmonic ◽  
Accurate Design ◽  
Electronic Signal Processing ◽  
Ultrahigh Frequencies

Graphene is conceivably the most nonlinear optoelectronic material we know. Its nonlinear optical coefficients in the terahertz frequency range surpass those of other materials by many orders of magnitude. Here, we show that the terahertz nonlinearity of graphene, both for ultrashort single-cycle and quasi-monochromatic multicycle input terahertz signals, can be efficiently controlled using electrical gating, with gating voltages as low as a few volts. For example, optimal electrical gating enhances the power conversion efficiency in terahertz third-harmonic generation in graphene by about two orders of magnitude. Our experimental results are in quantitative agreement with a physical model of the graphene nonlinearity, describing the time-dependent thermodynamic balance maintained within the electronic population of graphene during interaction with ultrafast electric fields. Our results can serve as a basis for straightforward and accurate design of devices and applications for efficient electronic signal processing in graphene at ultrahigh frequencies.

Sign in / Sign up

Export Citation Format

Share Document