Clue to a thorough understanding of terahertz pulse generation by femtosecond laser filamentation

Zhao, Jiayu; Liu, Weiwei; Li, Shichang; Lu, Dan; Zhang, Yizhu; Peng, Yan; Zhu, Yiming; Zhuang, Songlin

doi:10.1364/prj.6.000296

Cited by 30 publications

(12 citation statements)

References 40 publications

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“…For our work, it is totally associated with the single-color laser pumping THz wave generation scheme. In other situations, e.g., in field of two-color laser excitation, four-wave mixing (4WM) and transient photocurrent (PC) models were successfully combined by building their intrinsic connections during photo-ionization of air [23][24][25].…”

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confidence: 99%

Traveling-wave antenna model for terahertz radiation from laser-plasma interactions

et al. 2022

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Generation of terahertz (THz) wave from air plasma induced by femtosecond laser pulses with a single central frequency (the so-called "single-color") is one of the fundamental interactions between light and matter, and is also the basis of subsequent pumping schemes using two- or multi-color laser fields. Recently, more states of media beyond gas (e.g., atomic cluster and liquid) via photo-ionization have brought new experimental observations of THz radiation, which can no longer be simply attributed to the mainstream model of the transition-Cherenkov radiation (TCR), thus making the whole picture unclear. Here, we revisited the mechanism of this dynamic process in a new view of the traveling-wave antenna (TWA) model. By successfully reproducing the reported far-field THz radiation profiles from various plasma filament arrangements, the wide applicability of the TWA theory has been revealed. On the other hand in the microscopic view, we investigated the plasma oscillation during filamentation aiming at further bridging the plasma filament and the antenna. Accordingly, THz-plasma resonance has been theoretically and experimentally demonstrated as the elementary THz emitter, paving the way towards fully understanding this important single-color plasma based THz source.

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confidence: 99%

Traveling-wave antenna model for terahertz radiation from laser-plasma interactions

et al. 2022

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“…Beyond this range, photocurrents play a significant role and THz AAVBs are produced instead of THz FVBs or THz IVBs after centimeter-scale propagation. Specifically, it has been demonstrated theoretically and experimentally that both Kerr nonlinearity and plasma currents contribute to THz generation during filamentation since filamentation is the result of dynamical balance between the Kerr self-focusing and plasma defocusing [43,44]. Basically, they dominate at different pump laser intensities and filament lengths, and contribute to different THz frequency ranges [32][33][34][35][36].…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Generation of terahertz radiation with fractional or integer OAMs from a fractional-order vortex two-color field

Wang

Chen

et al. 2022

New J. Phys.

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This paper investigates the generation of the ultra-broadwidth (0.1-30 THz) terahertz (THz) radiation carrying fractional/integer orbital angular momentums (OAMs) via the interaction of the two-color (ω0 and 2ω0) laser field carrying initial fractional topological charges (TCs) with air in a moderate pump intensity regime (20 TW/cm2<Ipump<50 TW/cm2). The two four-wave mixing (FWM) processes (i.e., ω0+ω′0-2ω0→ωTHz and 2ω0-ω0-ω′0→ωTHz) are responsible for THz generation. The two processes can produce two THz pulses. They interfere with each other and THz interference vortex beams are obtained. More importantly, the generation probability from the first FWM process grows while that of the second process declines in the positive frequency region over distance. This is largely due to the combined action of phase mismatch and the blue shift of the THz center frequency. For a longer distance, THz fractional/integer vortex beams (FVBs/IVBs) are produced by the dominant FWM process (ω0+ω′0-2ω0→ωTHz). Therefore, via employing different combinations of the initial TCs of the ω0 and 2ω0 pulses, one can manipulate the generation of the THz vortex beams with arbitrary fractional-order or integer-order TCs at some specific propagation distances. What is even more interesting is that, when employing half-integer TCs, THz FVBs with varying TC over distance can be produced, companied with birth and annihilation of the alternative vortex pair. This is principally due to diffraction-related effects and the unstable nature of the fractional vortex structures. This simple manipulation for THz waves carrying arbitrary fractional or integer TCs in this scheme encourages the applications for optically rotation, manipulation of molecular or cell assays and image edge enhancement in the field of biomedicine.

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“…Compared with the microwaves, THz wave features shorter wavelength, higher energy and higher spatial resolution, etc. ; thus, it was found in applications for security, medical, manufacture sectors [45], imaging [46][47][48], detection [49] and wireless communications. In the recent years, some metasurfaces such as graphene [50,51] are applied at THz band to improve the system performance [52,53].…”

Section: Introductionmentioning

confidence: 99%

Beam reconfigurable holographic artificial impedance surface at terahertz band

Yao¹,

Li²

2019

J. Phys. D: Appl. Phys.

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A novel design method to achieve beam reconfigurable holographic artificial impedance surface (HAIS) is proposed in this article. Modified modulation equations are presented to achieve the desired single main beam radiation, whereas mushroom-shaped high-impedance surface is introduced to suppress the side lobes. Furthermore, a method called matrix approximation is proposed for the first time, and based on this, reconfigurable radiation beams are implemented. For demonstration purposes, a prototype HAIS is designed at THz band. The demonstrator has a size of approximately 4.7λ × 3.5λ, where λ is the wavelength in free space at 1 THz. Results indicate that along the desired elevation angles, reconfigurable radiation beams at −70°, −60°, −40°, 0°, 40°, 60°, and 70° can be achieved, where all radiations are single main beams. Compared to the conventional metasurface and pattern reconfigurable antenna arrays, the proposed HAIS characterizes low profile and high gain, while avoiding complex feeding networks. All discussions are numerically evaluated and validated by a beam reconfigurable HAIS.

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Clue to a thorough understanding of terahertz pulse generation by femtosecond laser filamentation

Cited by 30 publications

References 40 publications

Traveling-wave antenna model for terahertz radiation from laser-plasma interactions

Traveling-wave antenna model for terahertz radiation from laser-plasma interactions

Generation of terahertz radiation with fractional or integer OAMs from a fractional-order vortex two-color field

Beam reconfigurable holographic artificial impedance surface at terahertz band

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