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Blair G, Sprangle P. Generation of rf radiation by low-intensity laser pulse trains in air. Phys Rev E 2023; 108:015203. [PMID: 37583240 DOI: 10.1103/physreve.108.015203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/09/2023] [Indexed: 08/17/2023]
Abstract
In this paper, we analyze and numerically simulate mechanisms for generating directed rf radiation by a low-intensity laser pulse train (LPT) propagating in air. The LPT ionizes the air, forming a plasma filament. The ionization process relies on the background level of radioactivity which plays an important role in initiating a collisional ionization process. In our model a low-intensity LPT photoionizes background negative ions (produced by ambient ionizing radiation) and provides the seed electrons necessary to initiate collisional ionization. The intensity of the LPT is far below tunneling ionization levels. The ponderomotive forces associated with the LPT and self-fields drive plasma oscillations predominately in the radial direction. The driven radial electron currents in turn generate directed rf radiation. As the plasma density builds up on axis, the later portion of the LPT can defocus and limit the interaction length. The spectrum of the rf radiation consists of the fundamental frequency associated with the pulse separation time as well as harmonics. The rf generation mechanism is analyzed using fluid equations which incorporate, among other things, the effects of background radioactivity, photoionization, collisional ionization, ponderomotive and space-charge effects, and electron attachment-recombination processes. As an example, for a specific set of parameters, the rf spectrum and intensity are compared to experimental data.
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Affiliation(s)
- Gavin Blair
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA; and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20740, USA
| | - Phillip Sprangle
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA; and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20740, USA
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2
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Gomel A, Gaulier G, Eeltink D, Brunetti M, Kasparian J. Two statistical regimes in the transition to filamentation. OPTICS EXPRESS 2023; 31:9973-9980. [PMID: 37157560 DOI: 10.1364/oe.483042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We experimentally investigate fluctuations in the spectrum of ultrashort laser pulses propagating in air, close to the critical power for filamentation. Increasing the laser peak power broadens the spectrum while the beam approaches the filamentation regime. We identify two regimes for this transition: In the center of the spectrum, the output spectral intensity increases continuously. In contrast, on the edges of the spectrum the transition implies a bimodal probability distribution function for intermediate incident pulse energies, where a high-intensity mode appears and grows at the expense of the original low-intensity mode. We argue that this dual behavior prevents the definition of a univoquial threshold for filamentation, shedding a new light on the long-standing lack of explicit definition of the boundary of the filamentation regime.
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3
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Jiao ZH, Song JH, Zhang S, Li XY, Wang GL, Zhao SF. Controllable waveform terahertz generation using rippled plasma driven by an inhomogeneous electrostatic field. OPTICS EXPRESS 2023; 31:442-451. [PMID: 36606978 DOI: 10.1364/oe.476888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
We theoretically present the waveform controls of terahertz (THz) radiations generated from homogeneous and rippled plasma within inhomogeneous external electrostatic field. The Particle-in-cell (PIC) simulations is implemented to demonstrate generation and controllability of three types of THz pulses: single frequency THz pulse in homogeneous plasma, broadband THz pulse and dual frequency THz pulse in rippled plasma. The single frequency THz pulse can be tuned via shifting the knob of electron density of homogeneous plasma. Waveform of broadband THz pulse can be regulated into an envelope-like shape by varying amplitude of electron density of rippled plasma. The two center frequencies' interval of dual frequency THz pulse can be controlled by wave numbers of density distribution of rippled plasma. This work provides a potential means to generate the dual frequency THz pulses with two harmonic frequencies (ω+Ωω, Ω=2) or incommensurate frequencies (ω+Ωω, Ω=1.7,1.8, 2.2…).
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4
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Characterization of Electromagnetic Pulses Generated from Plasma Associated with Laser Filaments-Excited Aluminum Alloy Interaction. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12126059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Femtosecond laser filament-generated plasma can generate electromagnetic pulses (EMPs). These pulses may reduce the instrument’s precision, and, hence, influence the accuracy of the experimental results. They may even cause widespread disruption by disabling of the electronic control systems or distribution networks of power plants. This study investigated the characteristics of EMPs generated from the interaction of filament-generated plasmas with a solid target in air. In this study, ultrafast laser filamentation was used to produce plasma, which was focused on a 3 mm-thick aluminum (Al) alloy target for interaction, and the spatial distribution and main contributors of the EMPs were systematically and extensively studied. The results showed that the EMPs generated from ultrafast laser filament interaction with the Al alloy target had the following characteristics: the EMP energy generated from laser filament interaction with solid targets is tens of times higher than that generated only from the femtosecond laser filament; the maximum EMP signals appeared at a 20°–80°detection angle. The relationship between the energy of EMPs and the width and energy of the laser pulses is presented and discussed. These findings are beneficial for gaining insight into the EMP generation mechanism, spatial distribution, and transmission, and for providing more information for the design of EMPs’ shielding.
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5
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Aliev YM, Frolov AA. Excitation of high-intensity terahertz surface modes of plasma slab under action of p-polarized two-frequency laser radiation. Phys Rev E 2022; 105:045203. [PMID: 35590642 DOI: 10.1103/physreve.105.045203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/24/2022] [Indexed: 06/15/2023]
Abstract
The excitation of the terahertz (THz) high-intensity surface modes when the two-frequency p-polarized laser radiation interacts with a plasma slab is studied. It was found that the significant amplification of the laser field in the plasma slab occurs when p-polarized laser radiation is incident at the angle of total reflection. It is shown that, under the action of laser radiation ponderomotive forces, the resonant excitation of the THz mode of the plasma slab occurs if the frequency difference of the laser fields coincides with the eigenfrequency of the surface mode. It is established that the giant increase in the energy flux density of the THz mode occurs when p-polarized laser radiation is incident at the angle of total reflection on the near-critical plasma slab with rare electron collisions if the conditions of resonant excitation are satisfied. It is shown that in this case the energy flux density of THz mode can significantly exceed the laser intensity.
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Affiliation(s)
- Yu M Aliev
- Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991, Russia
| | - A A Frolov
- Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991, Russia
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6
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Nikolaeva IA, Shipilo DE, Pushkarev DV, Rizaev GE, Mokrousova DV, Koribut AV, Grudtsyn YV, Panov NA, Seleznev LV, Liu W, Ionin AA, Kosareva OG. Flat-top THz directional diagram of a DC-biased filament. OPTICS LETTERS 2021; 46:5497-5500. [PMID: 34724510 DOI: 10.1364/ol.439901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/10/2021] [Indexed: 06/13/2023]
Abstract
In the experiment, the laser pulse (744 nm, 0.5 mJ, 90 fs) focused into the air gap between the plane electrodes biased by a 10 kV/cm field (DC-biased filament) produced terahertz (THz) radiation. At the selected frequencies of ν=0.3, 0.5, 1 THz, a wide flat-top angular distribution was measured by a bolometer rotating in the plane of the electrodes. The simulations based on the unidirectional pulse propagation equation with fine 0.01 THz resolution and 3 PHz frequency domain showed the transition of the THz directional diagram from the flat-top at ν≲1THz to the conical one at ν>8THz due to the destructive interference of THz waves from the ionization front propagating with the superluminal velocity. Refraction on the plasma is not the major factor in ring formation.
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7
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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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Jin Q, Yiwen E, Zhang XC. Terahertz aqueous photonics. FRONTIERS OF OPTOELECTRONICS 2021; 14:37-63. [PMID: 36637782 PMCID: PMC9743863 DOI: 10.1007/s12200-020-1070-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/13/2020] [Indexed: 05/14/2023]
Abstract
Developing efficient and robust terahertz (THz) sources is of incessant interest in the THz community for their wide applications. With successive effort in past decades, numerous groups have achieved THz wave generation from solids, gases, and plasmas. However, liquid, especially liquid water has never been demonstrated as a THz source. One main reason leading the impediment is that water has strong absorption characteristics in the THz frequency regime.A thin water film under intense laser excitation was introduced as the THz source to mitigate the considerable loss of THz waves from the absorption. Laser-induced plasma formation associated with a ponderomotive force-induced dipole model was proposed to explain the generation process. For the one-color excitation scheme, the water film generates a higher THz electric field than the air does under the identical experimental condition. Unlike the case of air, THz wave generation from liquid water prefers a sub-picosecond (200-800 fs) laser pulse rather than a femtosecond pulse (~50 fs). This observation results from the plasma generation process in water.For the two-color excitation scheme, the THz electric field is enhanced by one-order of magnitude in comparison with the one-color case. Meanwhile, coherent control of the THz field is achieved by adjusting the relative phase between the fundamental pulse and the second-harmonic pulse.To eliminate the total internal reflection of THz waves at the water-air interface of a water film, a water line produced by a syringe needle was used to emit THz waves. As expected, more THz radiation can be coupled out and detected. THz wave generation from other liquids were also tested.
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Affiliation(s)
- Qi Jin
- The Institute of Optics, University of Rochester, Rochester, NY 14627 USA
| | - E. Yiwen
- The Institute of Optics, University of Rochester, Rochester, NY 14627 USA
| | - Xi-Cheng Zhang
- The Institute of Optics, University of Rochester, Rochester, NY 14627 USA
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10
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Peng Y, Xu B, Zhou S, Sun Z, Xiao H, Zhao J, Zhu Y, Zhang XC, Mittleman DM, Zhuang S. Experimental measurement of the wake field in a plasma filament created by a single-color ultrafast laser pulse. Phys Rev E 2021; 102:063211. [PMID: 33466021 DOI: 10.1103/physreve.102.063211] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 12/02/2020] [Indexed: 11/06/2022]
Abstract
A laser plasma wake field in a single-color femtosecond laser filament determines the acceleration of ionized electrons, which affects the intensity and bandwidth of the emitted terahertz wave and is important for understanding the fundamental nonlinear process of THz generation. Since the THz wave generated by a laser wake field is extremely small and easily hidden by other THz generation mechanisms, no method exists to measure this wake field directly. In this paper, a simple and stable method for determining the amplitude of the laser plasma wake field is presented. Based on the cancellation of a positive laser plasma wake field and an external negative electric field, the "zero point" of the intensity of the generated THz wave at some frequency can be used to determine the exact amplitude of the corresponding laser plasma wake field. This finding opens an avenue toward the clarification of ultrafast electronic dynamic processes in laser-induced plasmas.
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Affiliation(s)
- Yan Peng
- Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Bowei Xu
- Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Shiwei Zhou
- Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Zhaozhao Sun
- Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Haicheng Xiao
- Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Jiayu Zhao
- Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Yiming Zhu
- Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Xi-Cheng Zhang
- The Institute of Optics, University of Rochester, Rochester, New York 14627, USA
| | - Daniel M Mittleman
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA
| | - Songlin Zhuang
- Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
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11
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Tamulienė V, Juškevičiūtė G, Buožius D, Vaičaitis V, Babushkin I, Morgner U. Influence of tunnel ionization to third-harmonic generation of infrared femtosecond laser pulses in air. Sci Rep 2020; 10:17437. [PMID: 33060640 PMCID: PMC7566598 DOI: 10.1038/s41598-020-74263-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/31/2020] [Indexed: 11/16/2022] Open
Abstract
Here we present an experimental as well as theoretical study of third-harmonic generation in tightly focused femtosecond filaments in air at the wavelength of \documentclass[12pt]{minimal}
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\begin{document}$$1.5 \,\upmu \hbox {m}$$\end{document}1.5μm. At low intensities, longitudinal phase matching is dominating in the formation of 3rd harmonics, whereas at higher intensities locked X-waves are formed. We provide the arguments that the X-wave formation is governed mainly by the tunnel-like ionization dynamics rather than by the multiphoton one. Despite of this fact, the impact of the ionization-induced nonlinearity is lower than the one from bound–bound transitions at all intensities.
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Affiliation(s)
- Viktorija Tamulienė
- Laser Research Center, Vilnius University, Saulėtekio 10, 10223, Vilnius, Lithuania
| | - Greta Juškevičiūtė
- Laser Research Center, Vilnius University, Saulėtekio 10, 10223, Vilnius, Lithuania
| | - Danas Buožius
- Laser Research Center, Vilnius University, Saulėtekio 10, 10223, Vilnius, Lithuania
| | - Virgilijus Vaičaitis
- Laser Research Center, Vilnius University, Saulėtekio 10, 10223, Vilnius, Lithuania
| | - Ihar Babushkin
- Institute of Quantum Optics, Leibniz University of Hannover, Hannover, Germany. .,Max Born Institute, Max-Born-Straße 2A, 12489, Berlin, Germany. .,Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering-Innovation Across Disciplines), Welfengarten 1, 30167, Hannover, Germany.
| | - Uwe Morgner
- Institute of Quantum Optics, Leibniz University of Hannover, Hannover, Germany.,Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering-Innovation Across Disciplines), Welfengarten 1, 30167, Hannover, Germany
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12
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Singh D, Malik HK. Terahertz emission by multiple resonances under external periodic electrostatic field. Phys Rev E 2020; 101:043207. [PMID: 32422794 DOI: 10.1103/physreve.101.043207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 03/04/2020] [Indexed: 06/11/2023]
Abstract
In the presence of electron neutral collisions of a frequency (ν) of the order of ν≥0.5ω_{p}(ω_{p} is the plasma frequency), the collisional effects play an adverse role in the mechanism of terahertz (THz) radiation. The present work describes an approach for the efficient emission of THz radiation with the application of an external periodic electric field in the density rippled collisional plasma wherein an additional transverse component of the current is generated that adds to the THz radiation mechanism. The THz field obtained by coupling of the lasers' field with the external field is termed as an external field induced THz (EFIT). Here, the periodic wave number of the external field enables tuning of the THz radiation and helps achieve multiple resonance conditions for the excitation of large amplitude nonlinear plasma currents.
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Affiliation(s)
- Divya Singh
- Department of Physics & Electronics, Rajdhani College, University of Delhi, New Delhi 110015, India
| | - Hitendra K Malik
- PWAPA Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
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Franke P, Turnbull D, Katz J, Palastro JP, Begishev IA, Bromage J, Shaw JL, Boni R, Froula DH. Measurement and control of large diameter ionization waves of arbitrary velocity. OPTICS EXPRESS 2019; 27:31978-31988. [PMID: 31684419 DOI: 10.1364/oe.27.031978] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 09/30/2019] [Indexed: 06/10/2023]
Abstract
Large diameter, flying focus driven ionization waves of arbitrary velocity (IWAV's) were produced by a defocused laser beam in a hydrogen gas jet, and their spatial and temporal electron density characteristics were measured using a novel, spectrally resolved interferometry diagnostic. A simple analytic model predicts the effects of power spectrum non-uniformity on the IWAV trajectory and transverse profile. This model compares well with the measured data and suggests that spectral shaping can be used to customize IWAV behavior and increase controlled propagation of ionization fronts for plasma-photonics applications.
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14
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Englesbe A, Elle J, Reid R, Lucero A, Pohle H, Domonkos M, Kalmykov S, Krushelnick K, Schmitt-Sody A. Gas pressure dependence of microwave pulses generated by laser-produced filament plasmas. OPTICS LETTERS 2018; 43:4953-4956. [PMID: 30320792 DOI: 10.1364/ol.43.004953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 09/14/2018] [Indexed: 06/08/2023]
Abstract
The plasma arising due to the propagation of a filamenting ultrafast laser pulse in air contains currents driven by the pulse that generate radiated electromagnetic fields. We report absolutely calibrated measurements of the frequency spectrum of microwaves radiated by the filament plasma from 2-40 GHz. The emission pattern of the electric field spectrum is mapped as a function of air pressure from atmosphere to 0.5 Torr. For fixed laser pulse energy, duration, and focal geometry, we observe that decreasing the air pressure by a factor of approximately 103 increases the amplitude of the electric field waveform by a factor of about 40. As the air pressure decreases, the lower frequency components (<10 GHz) increase in amplitude faster than those at higher frequencies (>20 GHz). To the best of our knowledge, this behavior has not been observed before, is not predicted by existing theory, and implies the existence of a radiation mechanism in the plasma distinct from that which emits at terahertz frequencies.
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15
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Brée C, Hofmann M, Demircan A, Morgner U, Kosareva O, Savel'ev A, Husakou A, Ivanov M, Babushkin I. Symmetry Breaking and Strong Persistent Plasma Currents via Resonant Destabilization of Atoms. PHYSICAL REVIEW LETTERS 2017; 119:243202. [PMID: 29286725 DOI: 10.1103/physrevlett.119.243202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Indexed: 06/07/2023]
Abstract
The ionization rate of an atom in a strong optical field can be resonantly enhanced by the presence of long-living atomic levels (so-called Freeman resonances). This process is most prominent in the multiphoton ionization regime, meaning that the ionization event takes many optical cycles. Nevertheless, here, we show that these resonances can lead to rapid subcycle-scale plasma buildup at the resonant values of the intensity in the pump pulse. The fast buildup can break the cycle-to-cycle symmetry of the ionization process, resulting in the generation of persistent macroscopic plasma currents which remain after the end of the pulse. This, in turn, gives rise to a broadband radiation of unusual spectral structure, forming a comb from terahertz to visible. This radiation contains fingerprints of the attosecond electron dynamics in Rydberg states during ionization.
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Affiliation(s)
- C Brée
- Weierstrass Institute, Mohrenstrasse 39, 10117 Berlin, Germany
| | - M Hofmann
- Virtimo AG, Münzstrasse 5, 10178 Berlin, Germany
| | - A Demircan
- Institute for Quantum Optics, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
- Hannover Centre for optical Technologies, Nienburger Strasse 17, 30167 Hannover, Germany
| | - U Morgner
- Institute for Quantum Optics, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
- Hannover Centre for optical Technologies, Nienburger Strasse 17, 30167 Hannover, Germany
| | - O Kosareva
- Physics Faculty, Lomonosov Moscow State University, Leninskie gory 1-62, 119991 Moscow, Russia
| | - A Savel'ev
- Physics Faculty, Lomonosov Moscow State University, Leninskie gory 1-62, 119991 Moscow, Russia
| | - A Husakou
- Max Born Institute, Max Born Strasse 2a, 12489 Berlin, Germany
| | - M Ivanov
- Max Born Institute, Max Born Strasse 2a, 12489 Berlin, Germany
| | - I Babushkin
- Institute for Quantum Optics, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
- Max Born Institute, Max Born Strasse 2a, 12489 Berlin, Germany
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16
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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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17
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Thiele I, Nuter R, Bousquet B, Tikhonchuk V, Skupin S, Davoine X, Gremillet L, Bergé L. Theory of terahertz emission from femtosecond-laser-induced microplasmas. Phys Rev E 2017; 94:063202. [PMID: 28085420 DOI: 10.1103/physreve.94.063202] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Indexed: 11/07/2022]
Abstract
We present a theoretical investigation of terahertz (THz) generation in laser-induced gas plasmas. The work is strongly motivated by recent experimental results on microplasmas, but our general findings are not limited to such a configuration. The electrons and ions are created by tunnel ionization of neutral atoms, and the resulting plasma is heated by collisions. Electrons are driven by electromagnetic, convective, and diffusive sources and produce a macroscopic current which is responsible for THz emission. The model naturally includes both ionization current and transition-Cherenkov mechanisms for THz emission, which are usually investigated separately in the literature. The latter mechanism is shown to dominate for single-color multicycle laser pulses, where the observed THz radiation originates from longitudinal electron currents. However, we find that the often discussed oscillations at the plasma frequency do not contribute to the THz emission spectrum. In order to predict the scaling of the conversion efficiency with pulse energy and focusing conditions, we propose a simplified description that is in excellent agreement with rigorous particle-in-cell simulations.
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Affiliation(s)
- I Thiele
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - R Nuter
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - B Bousquet
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - V Tikhonchuk
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - S Skupin
- Univ. Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 33405 Talence, France
| | - X Davoine
- CEA, DAM, DIF, 91297 Arpajon, France
| | | | - L Bergé
- CEA, DAM, DIF, 91297 Arpajon, France
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Terahertz radiation driven by two-color laser pulses at near-relativistic intensities: Competition between photoionization and wakefield effects. Sci Rep 2016; 6:26743. [PMID: 27255689 PMCID: PMC4891721 DOI: 10.1038/srep26743] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/05/2016] [Indexed: 11/26/2022] Open
Abstract
We numerically investigate terahertz (THz) pulse generation by linearly-polarized, two-color femtosecond laser pulses in highly-ionized argon. Major processes consist of tunneling photoionization and ponderomotive forces associated with transverse and longitudinal field excitations. By means of two-dimensional particle-in-cell (PIC) simulations, we reveal the importance of photocurrent mechanisms besides transverse and longitudinal plasma waves for laser intensities >1015 W/cm2. We demonstrate the following. (i) With two-color pulses, photoionization prevails in the generation of GV/m THz fields up to 1017 W/cm2 laser intensities and suddenly loses efficiency near the relativistic threshold, as the outermost electron shell of ionized Ar atoms has been fully depleted. (ii) PIC results can be explained by a one-dimensional Maxwell-fluid model and its semi-analytical solutions, offering the first unified description of the main THz sources created in plasmas. (iii) The THz power emitted outside the plasma channel mostly originates from the transverse currents.
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19
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Andreeva VA, Kosareva OG, Panov NA, Shipilo DE, Solyankin PM, Esaulkov MN, González de Alaiza Martínez P, Shkurinov AP, Makarov VA, Bergé L, Chin SL. Ultrabroad Terahertz Spectrum Generation from an Air-Based Filament Plasma. PHYSICAL REVIEW LETTERS 2016; 116:063902. [PMID: 26918992 DOI: 10.1103/physrevlett.116.063902] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 06/05/2023]
Abstract
We have solved the long-standing problem of the mechanism of terahertz (THz) generation by a two-color filament in air and found that both neutrals and plasma contribute to the radiation. We reveal that the contribution from neutrals by four-wave mixing is much weaker and higher in frequency than the distinctive plasma lower-frequency contribution. The former is in the forward direction while the latter is in a cone and reveals an abrupt down-shift to the plasma frequency. Ring-shaped spatial distributions of the THz radiation are shown to be of universal nature and they occur in both collimated and focusing propagation geometries. Experimental measurements of the frequency-angular spectrum generated by 130-fs laser pulses agree with numerical simulations based on a unidirectional pulse propagation model.
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Affiliation(s)
- V A Andreeva
- Faculty of Physics, Lomonosov Moscow State University, 119991 Leninskie gori 1/2, Moscow, Russia
| | - O G Kosareva
- Faculty of Physics, Lomonosov Moscow State University, 119991 Leninskie gori 1/2, Moscow, Russia
- International Laser Center, Lomonosov Moscow State University, 119991 Leninskie gori 1/62, Moscow, Russia
| | - N A Panov
- International Laser Center, Lomonosov Moscow State University, 119991 Leninskie gori 1/62, Moscow, Russia
| | - D E Shipilo
- Faculty of Physics, Lomonosov Moscow State University, 119991 Leninskie gori 1/2, Moscow, Russia
| | - P M Solyankin
- Faculty of Physics, Lomonosov Moscow State University, 119991 Leninskie gori 1/2, Moscow, Russia
| | - M N Esaulkov
- Institute on Laser and Information Technologies of the Russian Academy of Sciences (ILIT RAS), 140700 Shatura, Russia
| | | | - A P Shkurinov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Leninskie gori 1/2, Moscow, Russia
- International Laser Center, Lomonosov Moscow State University, 119991 Leninskie gori 1/62, Moscow, Russia
| | - V A Makarov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Leninskie gori 1/2, Moscow, Russia
- International Laser Center, Lomonosov Moscow State University, 119991 Leninskie gori 1/62, Moscow, Russia
| | - L Bergé
- CEA-DAM, DIF, 91297 Arpajon, France
| | - S L Chin
- Département de Physique, de Génie Physique et d'Optique, Centre d'Optique, Photonique et Laser (COPL), Université Laval, Québec, QC G1V 0A6, Canada
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20
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Couairon A, Kosareva OG, Panov NA, Shipilo DE, Andreeva VA, Jukna V, Nesa F. Propagation equation for tight-focusing by a parabolic mirror. OPTICS EXPRESS 2015; 23:31240-31252. [PMID: 26698752 DOI: 10.1364/oe.23.031240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Part of the chain in petawatt laser systems may involve extreme focusing conditions for which nonparaxial and vectorial effects have high impact on the propagation of radiation. We investigate the possibility of using propagation equations to simulate numerically the focal spot under these conditions. We derive a unidirectional propagation equation for the Hertz vector, describing linear and nonlinear propagation under situations where nonparaxial diffraction and vectorial effects become significant. By comparing our simulations to the results of vector diffraction integrals in the case of linear tight-focusing by a parabolic mirror, we establish a practical criterion for the critical f -number below which initializing a propagation equation with a parabolic input phase becomes inaccurate. We propose a method to find suitable input conditions for propagation equations beyond this limit. Extreme focusing conditions are shown to be modeled accurately by means of numerical simulations of the unidirectional Hertz-vector propagation equation initialized with suitable input conditions.
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21
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Borodin AV, Panov NA, Kosareva OG, Andreeva VA, Esaulkov MN, Makarov VA, Shkurinov AP, Chin SL, Zhang XC. Transformation of terahertz spectra emitted from dual-frequency femtosecond pulse interaction in gases. OPTICS LETTERS 2013; 38:1906-1908. [PMID: 23722785 DOI: 10.1364/ol.38.001906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate that the two basic physical mechanisms of terahertz (THz) generation in a femtosecond filament, namely, the free electron photocurrent and the nonlinear polarization of neutrals, can be identified through the spectral analysis of THz radiation. The contribution from the photocurrent peaks at the units of THz, while the neutrals yield the peak at the tens of THz. We suggest the practical implementation of such spectral analysis by varying the initial transform-limited laser pulse duration.
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Affiliation(s)
- A V Borodin
- Department of Physics and International Laser Center, Lomonosov Moscow State University, Moscow 119923, Russia
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22
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Durand M, Jarnac A, Liu Y, Prade B, Houard A, Tikhonchuk V, Mysyrowicz A. Dynamics of plasma gratings in atomic and molecular gases. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:036405. [PMID: 23031032 DOI: 10.1103/physreve.86.036405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Indexed: 06/01/2023]
Abstract
The decay of the plasma grating formed at the intersection of two femtosecond filaments is measured in several molecular and atomic gases. The grating evolution is ruled by ambipolar diffusion in atomic gases and by a combination of ambipolar diffusion and collision-assisted free electron recombination in molecular gases. Electron diffusion and recombination coefficients are extracted for Ne, Ar, Kr, Xe, N2, O2, CO2, and air at 1 bar.
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Affiliation(s)
- M Durand
- Laboratoire d'Optique Appliquée, ENSTA ParisTech, Ecole Polytechnique, CNRS, 91761, Palaiseau, France
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23
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Jin Z, Chen ZL, Zhuo HB, Kon A, Nakatsutsumi M, Wang HB, Zhang BH, Gu YQ, Wu YC, Zhu B, Wang L, Yu MY, Sheng ZM, Kodama R. Tunable radiation source by coupling laser-plasma-generated electrons to a periodic structure. PHYSICAL REVIEW LETTERS 2011; 107:265003. [PMID: 22243162 DOI: 10.1103/physrevlett.107.265003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Indexed: 05/31/2023]
Abstract
Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on a solid target, with a metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that the radiation is caused by the Smith-Purcell mechanism. The results here indicate that tunable terahertz radiation with tens GV/m field strength can be achieved by using appropriate grating parameters.
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Affiliation(s)
- Z Jin
- Photon Pioneers Center, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871 Japan
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24
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Smeenk CTL, Arissian L, Zhou B, Mysyrowicz A, Villeneuve DM, Staudte A, Corkum PB. Partitioning of the linear photon momentum in multiphoton ionization. PHYSICAL REVIEW LETTERS 2011; 106:193002. [PMID: 21668148 DOI: 10.1103/physrevlett.106.193002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Indexed: 05/30/2023]
Abstract
The balance of the linear photon momentum in multiphoton ionization is studied experimentally. In the experiment argon and neon atoms are singly ionized by circularly polarized laser pulses with a wavelength of 800 and 1400 nm in the intensity range of 10(14)-10(15) W/cm2. The photoelectrons are measured using velocity map imaging. We find that the photoelectrons carry linear momentum corresponding to the photons absorbed above the field free ionization threshold. Our finding has implications for concurrent models of the generation of terahertz radiation in filaments.
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Affiliation(s)
- C T L Smeenk
- JASLab, University of Ottawa and National Research Council, 100 Sussex Drive, Ottawa, Canada
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25
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Wu HC, Meyer-Ter-Vehn J, Ruhl H, Sheng ZM. Terahertz radiation from a laser plasma filament. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:036407. [PMID: 21517604 DOI: 10.1103/physreve.83.036407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 01/16/2011] [Indexed: 05/30/2023]
Abstract
By the use of two-dimensional particle-in-cell simulations, we clarify the terahertz (THz) radiation mechanism from a plasma filament formed by an intense femtosecond laser pulse. The nonuniform plasma density of the filament leads to a net radiating current for THz radiation. This current is mainly located within the pulse and the first cycle of the wakefield. As the laser pulse propagates, a single-cycle and radially polarized THz pulse is constructively built up forward. The single-cycle shape is mainly due to radiation damping effect.
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Affiliation(s)
- H-C Wu
- Max-Planck-Institut für Quantenoptik, D-85748 Garching, Germany.
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26
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Zharova NA, Mironov VA, Fadeev DA. Anisotropic effects of terahertz emission from laser sparks in air. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:056409. [PMID: 21230604 DOI: 10.1103/physreve.82.056409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Indexed: 05/30/2023]
Abstract
Strong terahertz (THz) radiation can be generated by intense femtosecond laser pulses propagating in air. The excitation of transient current induced in the wake just behind the laser pulse is studied in detail using numerical simulations on the basis of Maxwell's equations for THz-band fields and hydrodynamic model for the plasma motion. It is shown that the thermal effects, anisotropic in character in the case of linear polarized laser field, can explain observed quadrupole-type THz radiation pattern in the experiment performed by Akhmedzhanov [Radiophys. Quantum Electron. 52, 482 (2009)]. Taking into account the transverse structure of the plasma filament, our numerical code enables us to calculate the spatial distribution and temporal evolution of terahertz electron current, its spectrum, and angular emission pattern. It is shown that an expansion of full fields in terms of azimuthal modes is a useful tool for research of THz generation in many situations of practical interest.
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Affiliation(s)
- N A Zharova
- Institute of Applied Physics, Russian Academy of Sciences, 46 Ulianov Street, Nizhny Novgorod 603950, Russia
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27
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Babushkin I, Kuehn W, Köhler C, Skupin S, Bergé L, Reimann K, Woerner M, Herrmann J, Elsaesser T. Ultrafast spatiotemporal dynamics of terahertz generation by ionizing two-color femtosecond pulses in gases. PHYSICAL REVIEW LETTERS 2010; 105:053903. [PMID: 20867920 DOI: 10.1103/physrevlett.105.053903] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Indexed: 05/29/2023]
Abstract
We present a combined theoretical and experimental study of spatiotemporal propagation effects in terahertz (THz) generation in gases using two-color ionizing laser pulses. The observed strong broadening of the THz spectra with increasing gas pressure reveals the prominent role of spatiotemporal reshaping and of a plasma-induced blueshift of the pump pulses in the generation process. Results obtained from (3+1)-dimensional simulations are in good agreement with experimental findings and clarify the mechanisms responsible for THz emission.
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Affiliation(s)
- I Babushkin
- Weierstraß-Institut für Angewandte Analysis und Stochastik, 10117 Berlin, Germany
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28
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Babushkin I, Skupin S, Herrmann J. Generation of terahertz radiation from ionizing two-color laser pulses in Ar filled metallic hollow waveguides. OPTICS EXPRESS 2010; 18:9658-9663. [PMID: 20588814 DOI: 10.1364/oe.18.009658] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The generation of THz radiation from ionizing two-color femtosecond pulses propagating in metallic hollow waveguides filled with Ar is numerically studied. We observe a strong reshaping of the low-frequency part of the spectrum. More precisely, after several millimeters of propagation the spectrum is extended from hundreds of GHz up to approximately 150 THz. For longer propagation distances, nearly single-cycle near-infrared pulses with wavelengths around 4.5 microm are obtained by appropriate spectral filtering, with an efficiency of 0.1-1%.
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Affiliation(s)
- I Babushkin
- Weierstrass-Institut für Angewandte Analysis und Stochastik, 10117 Berlin, Germany
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29
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Peñano J, Sprangle P, Hafizi B, Gordon D, Serafim P. Terahertz generation in plasmas using two-color laser pulses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:026407. [PMID: 20365665 DOI: 10.1103/physreve.81.026407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Indexed: 05/29/2023]
Abstract
We analyze the generation of terahertz radiation when an intense, short laser pulse is mixed with its frequency-doubled counterpart in plasma. The nonlinear coupling of the fundamental and the frequency-doubled laser pulses in plasma is shown to be characterized by a third order susceptibility which has a time dependence characteristic of the laser pulse durations. The terahertz generation process depends on the relative polarizations of the lasers and the terahertz frequency is omega approximately 1/tau(L), where tau(L) is the laser pulse duration. Since the laser pulse duration is typically in the picosecond or subpicosecond regime the resulting radiation is in the terahertz or multiterahertz regime. To obtain the third order susceptibility we solve the plasma fluid equations correct to third order in the laser fields, including both the relativistic and ponderomotive force terms. The relativistic and ponderomotive contributions to the susceptibility nearly cancel in the absence of electron collisions. Therefore, in this terahertz generation mechanism collisional effects play a critical role. Consistent with recent experimental observations, our model shows that (1) the terahertz field amplitude is proportional to I(1) square root I(2), where I(1) and I(2) are the intensities of the fundamental and second harmonic laser pulses, respectively, (2) the terahertz emission is maximized when the polarization of the laser beams and the terahertz are aligned, (3) for typical experimental parameters, the emitted terahertz field amplitude is on the order of tens of kilovolts/cm with duration comparable to that of the drive laser pulses, and (4) the direction of terahertz emission depends sensitively on experimental parameters.
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Affiliation(s)
- Joseph Peñano
- Naval Research Laboratory, Plasma Physics Division, Washington, DC 20375, USA
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30
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Kostin VA, Vvedenskii NV. Ionization-induced conversion of ultrashort Bessel beam to terahertz pulse. OPTICS LETTERS 2010; 35:247-249. [PMID: 20081983 DOI: 10.1364/ol.35.000247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We examine the conical terahertz emission from the superluminous ionization front created in air by an axicon-focused femtosecond laser pulse. We develop the theoretical model that explains the experimental results and predicts new possibilities to control terahertz pulse parameters.
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Affiliation(s)
- V A Kostin
- Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov Street, Nizhny Novgorod 603950, Russia
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31
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Nakagawa M, Kodama R, Higashiguchi T, Yugami N. Generation of terahertz radiation via an electromagnetically induced transparency at ion acoustic frequency region in laser-produced dense plasmas. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:025402. [PMID: 19792190 DOI: 10.1103/physreve.80.025402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Indexed: 05/28/2023]
Abstract
Electromagnetically induced transparency is a well-known quantum phenomena that electromagnetic wave controls the refractive index of medium. It enables us to create a passband for low-frequency electromagnetic wave in a dense plasma even if the plasma is opaque for the electromagnetic wave. This technique can be used to prove the ion acoustic wave because the ion acoustic frequency is lower than the plasma frequency. We have investigated a feasibility of electromagnetic radiation at THz region corresponding to the ion acoustic frequency from a dense plasma. We confirmed that the passband is created at about 7.5 THz corresponding to the ion acoustic frequency in the electron plasma density of 10(21) cm(-3) with a Ti:Sapphire laser with the wavelength of 800 nm and the laser intensity of 10(17) W/cm(2). The estimated radiation power is around 1 MW, which is expected to be useful for nonlinear THz science and applications.
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Affiliation(s)
- Makoto Nakagawa
- Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871, Japan
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32
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Husakou A, Herrmann J. High-power, high-coherence supercontinuum generation in dielectric-coated metallic hollow waveguides. OPTICS EXPRESS 2009; 17:12481-12492. [PMID: 19654649 DOI: 10.1364/oe.17.012481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this paper we theoretically study a novel approach for soliton-induced supercontinuum generation based on the application of metallic dielectric-coated hollow waveguides. The low loss of such waveguides permits the use of smaller diameters with enhanced dispersion control and enables the generation of two-octave-broad spectra with unprecedentedly high spectral peak power densities up to five orders of magnitude larger than in standard PCFs with high coherence. The predicted high coherence of the supercontinuum is related to the coherent seed components formed by the abruptly rising plasma density. We also predict that high-power supercontinua in the vacuum ultraviolet can be generated in such waveguides.
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Affiliation(s)
- A Husakou
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy Max Born Str. 2a, D-12489 Berlin, Germany.
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33
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Manceau JM, Averchi A, Bonaretti F, Faccio D, Di Trapani P, Couairon A, Tzortzakis S. Terahertz pulse emission optimization from tailored femtosecond laser pulse filamentation in air. OPTICS LETTERS 2009; 34:2165-2167. [PMID: 19823536 DOI: 10.1364/ol.34.002165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We study the generation of intense terahertz pulses produced by two-color laser pulse filamentation in air. We tailor the filamentation process and the produced plasma strings and study how the generated terahertz field is modified. An important terahertz pulse shortening is found for plasma strings with uniform electron density.
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Affiliation(s)
- J-M Manceau
- Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion, Greece
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34
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Dong XG, Sheng ZM, Wu HC, Wang WM, Zhang J. Single-cycle strong terahertz pulse generation from a vacuum-plasma interface driven by intense laser pulses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:046411. [PMID: 19518363 DOI: 10.1103/physreve.79.046411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2008] [Indexed: 05/27/2023]
Abstract
Single-cycle strong terahertz pulses can be generated by irradiating ultrashort intense laser pulses onto a tenuous plasma slab. At the plasma surface, laser ponderomotive force accelerates electrons and induces net currents, which radiate terahertz pulses. Our theoretical model suggests that if tau_{L}>2pi/omega_{p}, with tau_{L} as the laser-pulse duration and omega_{p} as the plasma frequency, the emission frequency is around tau_{L};{-1}. On the other hand, the emission frequency is around omega_{p}/2pi if tau_{L}<2pi/omega_{p}. Our numerical simulations support the theoretical model, showing that such a terahertz source is capable of providing megawatt power, field strengths of MV/cm, and broad frequency tunability.
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Affiliation(s)
- X G Dong
- Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190, China
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35
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Chen M, Pukhov A, Peng XY, Willi O. Theoretical analysis and simulations of strong terahertz radiation from the interaction of ultrashort laser pulses with gases. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:046406. [PMID: 18999542 DOI: 10.1103/physreve.78.046406] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Indexed: 05/27/2023]
Abstract
Terahertz (THz) radiation from the interaction of ultrashort laser pulses with gases is studied both by theoretical analysis and particle-in-cell (PIC) simulations. A one-dimensional THz generation model based on the transient ionization electric current mechanism is given, which explains the results of one-dimensional PIC simulations. At the same time the relation between the final THz field and the initial transient ionization current is shown. One- and two-dimensional simulations show that for the THz generation the contribution of the electric current due to ionization is much larger than the one driven by the usual ponderomotive force. Ionization current generated by different laser pulses and gases is also studied numerically. Based on the numerical results we explain the scaling laws for THz emission observed in the recent experiments performed by Xie et al. [Phys. Rev. Lett. 96, 075005 (2006)]. We also study the effective parameter region for the carrier envelop phase measurement by the use of THz generation.
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Affiliation(s)
- Min Chen
- Institut für Theoretische Physik I, Heinrich-Heine-Universität Düsseldorf, 40225, Düseldorf, Germany.
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36
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D'Amico C, Houard A, Franco M, Prade B, Mysyrowicz A, Couairon A, Tikhonchuk VT. Conical forward THz emission from femtosecond-laser-beam filamentation in air. PHYSICAL REVIEW LETTERS 2007; 98:235002. [PMID: 17677911 DOI: 10.1103/physrevlett.98.235002] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Indexed: 05/16/2023]
Abstract
We attribute a strong forward directed THz emission from femtosecond laser filaments in air to a transition-Cherenkov emission from the plasma space charge moving behind the ionization front at light velocity. Distant targets can be easily irradiated by this new source of THz radiation.
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Affiliation(s)
- C D'Amico
- Laboratoire d'Optique Appliquée, ENSTA, Ecole Polytechnique, CNRS UMR 7639, Palaiseau, 91761 France
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37
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Wu HC, Sheng ZM, Dong QL, Xu H, Zhang J. Powerful terahertz emission from laser wakefields in inhomogeneous magnetized plasmas. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:016407. [PMID: 17358268 DOI: 10.1103/physreve.75.016407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 10/18/2006] [Indexed: 05/14/2023]
Abstract
Powerful coherent terahertz (THz) pulses with a broad spectrum (0.1-3 THz) can be produced from a laser-driven wakefield through linear mode conversion in inhomogeneous magnetized plasmas with the maximum plasma density of 10(17) cm(-3). This occurs when a laser pulse, with an optimized duration about 300 fs, is incident either normally or obliquely to the density gradient of inhomogeneous magnetized plasmas. The external dc magnetic field has a magnitude of a few tesla. By changing the strength and direction of the magnetic field, one can enhance or suppress the THz emission. The maximum energy conversion efficiency in the magnetized plasmas can be double that in the unmagnetized plasmas. Such wakefield emission can be a powerful THz source at the MW level and capable of affording field strength of a few MV/cm, suitable for THz nonlinear physics. Because these THz emissions are always with a positive chirp, with a proper dispersion compression, single-cycle THz pulses can be generated with higher peak powers and field strengths.
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Affiliation(s)
- Hui-Chun Wu
- Beijing National Laboratory for Condensed Matters, Institute of Physics, Chinese Academy of Science, Beijing 100080, China
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38
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Hoyer W, Knorr A, Moloney JV, Wright EM, Kira M, Koch SW. Photoluminescence and terahertz emission from femtosecond laser-induced plasma channels. PHYSICAL REVIEW LETTERS 2005; 94:115004. [PMID: 15903868 DOI: 10.1103/physrevlett.94.115004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Indexed: 05/02/2023]
Abstract
Luminescence as a mechanism for terahertz emission from femtosecond laser-induced plasmas is studied. By using a fully microscopic theory, Coulomb scattering between electrons and ions is shown to lead to luminescence even for a spatially homogeneous plasma. The spectral features introduced by the rod geometry of laser-induced plasma channels in air are discussed on the basis of a generalized mode-function analysis.
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Affiliation(s)
- W Hoyer
- Arizona Center for Mathematical Sciences and Optical Sciences Center, University of Arizona, Tucson, AZ 85721, USA.
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Sheng ZM, Mima K, Zhang J, Sanuki H. Emission of electromagnetic pulses from laser wakefields through linear mode conversion. PHYSICAL REVIEW LETTERS 2005; 94:095003. [PMID: 15783972 DOI: 10.1103/physrevlett.94.095003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2004] [Indexed: 05/24/2023]
Abstract
Powerful coherent emission around the plasma oscillation frequency can be produced from a laser wakefield through linear mode conversion. This occurs when the laser pulse is incident obliquely to the density gradient of inhomogeneous plasmas. The emission spectrum and conversion efficiency are obtained analytically, which are in agreement with particle-in-cell simulations. The emission can be tuned to be a radiation source in the terahertz region and with field strengths as large as a few GV/m, suitable for high-field applications. The emission also provides a simple way to measure the wakefield produced for particle acceleration.
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Affiliation(s)
- Zheng-Ming Sheng
- Laboratory of Optical Physics, Institute of Physics, CAS, Beijing 100080, China
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