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Zheltikov AM. Laser filaments as pulsed antennas. OPTICS LETTERS 2021; 46:4984-4987. [PMID: 34598248 DOI: 10.1364/ol.426023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Secondary radiation emission of laser-induced filaments is revisited from a perspective of transient antenna radiation. Solutions for transient-antenna radiation fields are shown to provide an accurate description of the spectral and polarization properties, radiation patterns, and the angular dispersion of terahertz and microwave radiation emitted by laser filaments. Time-domain pulsed-antenna analysis offers a physically clear explanation for the bandwidth of this radiation, relating the low-frequency cutoff in its spectrum to the filament length, thus explaining efficient microwave generation in laser filamentation experiments.
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Mitrofanov AV, Sidorov-Biryukov DA, Nazarov MM, Voronin AA, Rozhko MV, Fedotov AB, Zheltikov AM. Coherently enhanced microwave pulses from midinfrared-driven laser plasmas. OPTICS LETTERS 2021; 46:1081-1084. [PMID: 33649662 DOI: 10.1364/ol.410030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
Ultrafast ionization of a gas medium driven by ultrashort midinfrared laser pulses provides a source of bright ultrabroadband radiation whose spectrum spans across the entire microwave band, reaching for the sub-gigahertz range. We combine multiple, mutually complementary detection techniques to provide an accurate polarization-resolved characterization of this broadband output as a function of the gas pressure. At low gas pressures, the lowest-frequency part of this output is found to exhibit a drastic enhancement as this field builds up its coherence, developing a well-resolved emission cone, dominated by a radial radiation energy flux. This behavior of the intensity, coherence, and polarization of the microwave output is shown to be consistent with Cherenkov-type radiation by ponderomotively driven plasma currents.
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High-Energy, Short-Duration Bursts of Coherent Terahertz Radiation from an Embedded Plasma Dipole. Sci Rep 2018; 8:145. [PMID: 29317689 PMCID: PMC5760715 DOI: 10.1038/s41598-017-18399-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 12/11/2017] [Indexed: 11/08/2022] Open
Abstract
Emission of radiation from electrons undergoing plasma oscillations (POs) at the plasma frequency has attracted interest because of the existence of intriguing and non-trivial coupling mechanism between the electrostatic PO and the emitted electromagnetic wave. While broadband emission from plasma waves in inhomogeneous plasma is well known, the underlying physics of narrowband emission at the plasma frequency observed in experiments and in solar radio-bursts is obscure. Here we show that a spatially-localized plasma dipole oscillation (PDO) can be generated when electrons are trapped in a moving train of potential wells produced by the ponderomotive force of two slightly detuned laser pulses that collide in plasma and give rise to a burst of quasi-monochromatic radiation. The energy radiated in the terahertz spectral region can reach an unprecedented several millijoules, which makes it suitable for applications requiring short pulses of high-intensity, narrowband terahertz radiation.
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Thiele I, Zhou B, Nguyen A, Smetanina E, Nuter R, de Alaiza Martínez PG, Kaltenecker KJ, Déchard J, Bergé L, Jepsen PU, Skupin S. Resonant Effects in Terahertz Generation with Laser-Induced Gas Plasmas. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201819503011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Shkurinov AP, Sinko AS, Solyankin PM, Borodin AV, Esaulkov MN, Annenkov VV, Kotelnikov IA, Timofeev IV, Zhang XC. Impact of the dipole contribution on the terahertz emission of air-based plasma induced by tightly focused femtosecond laser pulses. Phys Rev E 2017; 95:043209. [PMID: 28505777 DOI: 10.1103/physreve.95.043209] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Indexed: 11/07/2022]
Abstract
The present paper studies the generation mechanism of terahertz (THz) radiation from tightly focused femtosecond laser pulses in a gas medium. We measured the angular radiation pattern under different focusing conditions and observed that, with the deepening of focus, the angular radiation pattern changes and optical-to-THz conversion efficiency increases. The analysis of the observed phenomena led to the assumption that the dipole radiation prevails in most cases despite the existing conception regarding the dominating role of the quadrupole mechanism of radiation. Based on these assumptions, the transient photocurrent theory of the phenomenon presented in this paper was developed by us and used for the numerical fit of the experimental data.
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Affiliation(s)
- Alexander P Shkurinov
- Department of Physics and International Laser Center, Lomonosov Moscow State University, Leninskie Gory, Moscow 119992, Russia.,Institute on Laser and Information Technologies of the Russian Academy of Sciences, Branch of the FSRC "Crystallography and Photonics" RAS, Shatura, Moscow Region 140700, Russia
| | - Anton S Sinko
- Department of Physics and International Laser Center, Lomonosov Moscow State University, Leninskie Gory, Moscow 119992, Russia
| | - Peter M Solyankin
- Department of Physics and International Laser Center, Lomonosov Moscow State University, Leninskie Gory, Moscow 119992, Russia.,Institute on Laser and Information Technologies of the Russian Academy of Sciences, Branch of the FSRC "Crystallography and Photonics" RAS, Shatura, Moscow Region 140700, Russia
| | - Alexander V Borodin
- Institute on Laser and Information Technologies of the Russian Academy of Sciences, Branch of the FSRC "Crystallography and Photonics" RAS, Shatura, Moscow Region 140700, Russia
| | - Mikhail N Esaulkov
- Institute on Laser and Information Technologies of the Russian Academy of Sciences, Branch of the FSRC "Crystallography and Photonics" RAS, Shatura, Moscow Region 140700, Russia
| | - Vladimir V Annenkov
- Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russia.,Novosibirsk State University, Novosibirsk 630090, Russia
| | - Igor A Kotelnikov
- Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russia.,Novosibirsk State University, Novosibirsk 630090, Russia
| | - Igor V Timofeev
- Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russia.,Novosibirsk State University, Novosibirsk 630090, Russia
| | - Xi-Cheng Zhang
- The Institute of Optics, University of Rochester, Rochester, New York 14627-0186, USA
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Nguyen A, González de Alaiza Martínez P, Déchard J, Thiele I, Babushkin I, Skupin S, Bergé L. Spectral dynamics of THz pulses generated by two-color laser filaments in air: the role of Kerr nonlinearities and pump wavelength. OPTICS EXPRESS 2017; 25:4720-4740. [PMID: 28380743 DOI: 10.1364/oe.25.004720] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We theoretically and numerically study the influence of both instantaneous and Raman-delayed Kerr nonlinearities as well as a long-wavelength pump in the terahertz (THz) emissions produced by two-color femtosecond filaments in air. Although the Raman-delayed nonlinearity induced by air molecules weakens THz generation, four-wave mixing is found to impact the THz spectra accumulated upon propagation via self-, cross-phase modulations and self-steepening. Besides, using the local current theory, we show that the scaling of laser-to-THz conversion efficiency with the fundamental laser wavelength strongly depends on the relative phase between the two colors, the pulse duration and shape, rendering a universal scaling law impossible. Scaling laws in powers of the pump wavelength may only provide a rough estimate of the increase in the THz yield. We confront these results with comprehensive numerical simulations of strongly focused pulses and of filaments propagating over meter-range distances.
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