scholarly journals Generation of ultrashort pulses in the THz frequency range

2021 ◽  
Vol 2103 (1) ◽  
pp. 012061
Author(s):  
Yu S Oparina ◽  
A V Savilov
Keyword(s):  
Electron Bunch ◽  
Ultrashort Pulses ◽  
Coulomb Repulsion ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Spontaneous Radiation ◽  
Terahertz Frequency Range ◽  
Single Wave ◽  
Radiation Fields ◽  
Wave Cycle

Abstract There are results for the spontaneous coherent super-radiative undulator emission in the terahertz frequency range from a short (as compared to the wavelength of the radiated wave) dense electron bunch. If the group velocity of the wave is close to the bunch velocity, this is a process of spontaneous radiation followed by amplification of a single wave cycle. Despite the Coulomb repulsion of electrons inside the bunch, its compactness is provided by the compression of the bunch under the action of its own radiation fields. As a result, formation of an ultra-short (several cycles long) powerful wave packet occurs when the bunch moves through several undulator periods with high (∼20% in optimized systems) efficiency of extraction of the electron energy and high intensity (∼ 100 MV/m) of the peak wave field.

scholarly journals Generation in the regime with three resonance frequencies

2021 ◽  
Vol 2103 (1) ◽  
pp. 012060
Author(s):  
Yu S Oparina ◽  
A V Savilov
Keyword(s):  
Electron Bunch ◽  
Wave Interaction ◽  
Particle Dynamics ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Electron Wave ◽  
Terahertz Frequency Range ◽  
Radiation Process ◽  
Resonance Frequencies ◽  
Phase Size

Abstract If the group velocity of the wave is close to the bunch velocity, the bunch placed in the maximumum of the radiated pulse. It provides high effeciency of the electron-wave interaction. However, there are other factors related to particle dynamics, which have strong influence on the radiation process. In this paper the regime with three resonance frequencies is discussed. By varying the phase size of the electron bunch, the generation conditions at each of the frequencies can be changed. There are results for the spontaneous coherent super-radiative undulator emission in the terahertz frequency range from a short (as compared to the wavelength of the radiated wave) dense electron bunch. As a result, an electron bunch radiates two pulses with amplitudes of the radiated fields ∼ 10-70 MV/m.

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.

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