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Latty KS, Borrero J, Arnaud T, Hartig KC. Excitation of optically trapped single particles using femtosecond pulses. OPTICS LETTERS 2024; 49:2169-2172. [PMID: 38621103 DOI: 10.1364/ol.519790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 03/21/2024] [Indexed: 04/17/2024]
Abstract
Excitation from optically trapped particles is examined through laser-induced breakdown spectroscopy following interactions with mJ-level fs pulses. Optical emissions from sub-ng ablation of precisely positioned cupric oxide microparticles are used as a method to spatially resolve laser-particle interactions resulting in excitation. External focusing lenses are often used to change the dynamics of nonlinear self-focusing of fs pulses to form laser filaments or, alternatively, to form very intense air plasmas. Given the significant implications external focusing has on laser propagation and plasma conditions, single-particle emissions are studied with focusing lenses ranging from 50 to 300 mm. It is shown that, while single particles are less excited at longer focal lengths due to limited energy transfer through laser-particle interactions, the cooler plasma results in a lower thermal background to reveal resolved single-shot emission peaks. By developing an understanding in the fundamental interaction that occurs between single particles and fs pulses and filaments, practical improvements can be made for atmospheric remote sensing of low-concentration aerosols.
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2
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Bak J, Urdaneta G, Pokharel S, Miles RB, Tropina A. Two-dimensional high resolution electron properties of femtosecond laser-induced plasma filament in atmospheric pressure argon. Sci Rep 2024; 14:3703. [PMID: 38355680 PMCID: PMC10867094 DOI: 10.1038/s41598-024-52868-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/24/2024] [Indexed: 02/16/2024] Open
Abstract
This work reports the measurement of two-dimensional electron properties over a nanosecond scale integration time across a femtosecond laser-induced plasma filament in atmospheric pressure argon. Radial electron properties across the [Formula: see text] [Formula: see text]m diameter filament are obtained at discrete axial locations at 2.5 mm steps by one-dimensional high-resolution laser Thomson scattering with a spatial resolution of 10 [Formula: see text]m. These measurements reveal plasma structural information in the filament. The Thomson spectral lineshapes exhibit clear spectral sidebands with an [Formula: see text] parameter [Formula: see text], enabling the measurement of both electron temperature and density profiles. These measurements yield electron densities on the order of [Formula: see text]/m[Formula: see text] and electron temperatures of [Formula: see text] eV. Heating from the probe laser due to inverse bremsstrahlung is taken into account to correct the Thomson scattering electron temperature measurements. Under these conditions, electron-neutral collision induced bremsstrahlung becomes the dominant laser-induced plasma heating process associated with the probe laser. The measurements reveal structural features of the filament, including an asymmetrically skewed density structure in the axial direction and reversed radial distributions of electron density and temperature.
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Affiliation(s)
- Junhwi Bak
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, 77845, USA.
| | - Gerardo Urdaneta
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, 77845, USA
| | - Sagar Pokharel
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, 77845, USA
| | - Richard B Miles
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, 77845, USA
| | - Albina Tropina
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, 77845, USA
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3
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Kwapis EH, Borrero J, Latty KS, Andrews HB, Phongikaroon SS, Hartig KC. Laser Ablation Plasmas and Spectroscopy for Nuclear Applications. APPLIED SPECTROSCOPY 2024; 78:9-55. [PMID: 38116788 DOI: 10.1177/00037028231211559] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
The development of measurement methodologies to detect and monitor nuclear-relevant materials remains a consistent and significant interest across the nuclear energy, nonproliferation, safeguards, and forensics communities. Optical spectroscopy of laser-produced plasmas is becoming an increasingly popular diagnostic technique to measure radiological and nuclear materials in the field without sample preparation, where current capabilities encompass the standoff, isotopically resolved and phase-identifiable (e.g., UO and UO2 ) detection of elements across the periodic table. These methods rely on the process of laser ablation (LA), where a high-powered pulsed laser is used to excite a sample (solid, liquid, or gas) into a luminous microplasma that rapidly undergoes de-excitation through the emission of electromagnetic radiation, which serves as a spectroscopic fingerprint for that sample. This review focuses on LA plasmas and spectroscopy for nuclear applications, covering topics from the wide-area environmental sampling and atmospheric sensing of radionuclides to recent implementations of multivariate machine learning methods that work to enable the real-time analysis of spectrochemical measurements with an emphasis on fundamental research and development activities over the past two decades. Background on the physical breakdown mechanisms and interactions of matter with nanosecond and ultrafast laser pulses that lead to the generation of laser-produced microplasmas is provided, followed by a description of the transient spatiotemporal plasma conditions that control the behavior of spectroscopic signatures recorded by analytical methods in atomic and molecular spectroscopy. High-temperature chemical and thermodynamic processes governing reactive LA plasmas are also examined alongside investigations into the condensation pathways of the plasma, which are believed to serve as chemical surrogates for fallout particles formed in nuclear fireballs. Laser-supported absorption waves and laser-induced shockwaves that accompany LA plasmas are also discussed, which could provide insights into atmospheric ionization phenomena from strong shocks following nuclear detonations. Furthermore, the standoff detection of trace radioactive aerosols and fission gases is reviewed in the context of monitoring atmospheric radiation plumes and off-gas streams of molten salt reactors. Finally, concluding remarks will present future outlooks on the role of LA plasma spectroscopy in the nuclear community.
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Affiliation(s)
- Emily H Kwapis
- Nuclear Engineering Program, Department of Materials Science and Engineering, University of Florida, Gainesville, Florida, USA
| | - Justin Borrero
- Nuclear Engineering Program, Department of Materials Science and Engineering, University of Florida, Gainesville, Florida, USA
| | - Kyle S Latty
- Nuclear Engineering Program, Department of Materials Science and Engineering, University of Florida, Gainesville, Florida, USA
| | - Hunter B Andrews
- Radioisotope Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | | | - Kyle C Hartig
- Nuclear Engineering Program, Department of Materials Science and Engineering, University of Florida, Gainesville, Florida, USA
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4
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Zhang Y, Xia Y, Liang C, Chen A, Li S, Jin M. Exploring the Femtosecond Filamentation Threshold in Liquid Media Using a Mach-Zehnder Interferometer. SENSORS (BASEL, SWITZERLAND) 2023; 23:9163. [PMID: 38005548 PMCID: PMC10675478 DOI: 10.3390/s23229163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/24/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023]
Abstract
We experimentally studied the supercontinuum induced by femtosecond filamentation in different liquid media. Using a Mach-Zehnder interferometer, we determined the relative filamentation thresholds (Pth) of these media. Research has shown that the value of the filamentation threshold is greater than that of Pcr (critical power for self-focusing), which can mainly be attributed to the strong dispersion effect. Changing the focal length of the focusing lens affects filamentation dynamics, thereby affecting the measured results regarding the filamentation threshold. With shorter focal lengths, the linear focusing (i.e., geometrical focusing) regime dominates, and the measured values of Pth for different liquid media are almost the same; as the focal length becomes larger, self-focusing starts to play a role, making the values of Pth for different media different from each other. This study presents an efficient method for investigating the femtosecond filamentation phenomenon in liquid media, helpful to provide further insights into the physical mechanism of supercontinuum generation via femtosecond filamentation in liquid media.
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Affiliation(s)
- Yun Zhang
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China; (Y.Z.); (Y.X.); (C.L.); (A.C.); (M.J.)
| | - Yu Xia
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China; (Y.Z.); (Y.X.); (C.L.); (A.C.); (M.J.)
| | - Canneng Liang
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China; (Y.Z.); (Y.X.); (C.L.); (A.C.); (M.J.)
| | - Anmin Chen
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China; (Y.Z.); (Y.X.); (C.L.); (A.C.); (M.J.)
| | - Suyu Li
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China; (Y.Z.); (Y.X.); (C.L.); (A.C.); (M.J.)
- Research Center for Intelligent Transportation, Zhejiang Laboratory, Hangzhou 311121, China
| | - Mingxing Jin
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China; (Y.Z.); (Y.X.); (C.L.); (A.C.); (M.J.)
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Zhang W, Chen J, Wang S, Li H, Zang H, Xu H. Energy deposition in a telescopic laser filament for the control of fuel ignition. OPTICS EXPRESS 2023; 31:33132-33140. [PMID: 37859100 DOI: 10.1364/oe.500042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/05/2023] [Indexed: 10/21/2023]
Abstract
The efficiency of energy coupled to plasma during femtosecond (fs) laser filamentation plays a decisive role in a variety of filament applications such as remote fabrication and spectroscopy. However, the energy deposition characterization in the fs laser filament formed by a telescope, which provides an efficient way to extend the filament distance, has not yet been revealed. In the present study, we show that when the distance between the two lenses in a telescope changes, i.e., the effective focal length changes, there exists an optimal plateau energy deposition region in which the energy deposited into the filament per unit length called the average lineic energy deposition (ALED) remains at high levels, exhibiting a remarkable difference from the monotonic change in a single-lens focusing system. As a proof of principle, we examined the influence of the energy deposition on the ignition of a lean methane/air mixture, and found that the use of the telescope can efficiently extend the ignition distance when compared with a single-lens focusing system under the same incident laser energy condition. Our results may help understand the energy deposition behaviors in a variety of telescopic filaments and provide more options to manipulating laser ignition at a desired distance.
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6
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Cao J, Fu Y, Wang T, Li H, Xu H. Air-laser-based coherent Raman spectroscopy of atmospheric molecules in a filamentary plasma grating. OPTICS LETTERS 2023; 48:4308-4311. [PMID: 37582019 DOI: 10.1364/ol.496658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/25/2023] [Indexed: 08/17/2023]
Abstract
Coherent Raman spectroscopy (CRS) with air-laser-based hybrid femtosecond/picosecond (fs/ps) pulses has shown promising potential for remote detection and surveillance of atmospheric species with high temporal and frequency resolution. Here, to enhance the sensitivity and extend the detection distance, we generate the CRS spectra of air molecules in situ in a filamentary plasma grating, and show that the grating can efficiently enhance the intensities of the coherent vibrational Raman lines of N2, O2, and N2 + by 2-3 orders of magnitude at an extended distance. By examining the intensities of the Raman lines, fs-pulsed supercontinuum, and ps-pulsed air laser produced under different grating conditions, we reveal that the optimization of the Raman lines is achieved by the dynamic balance between the supercontinuum-induced vibrational coherence and air-laser-induced polarization of the air species.
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7
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Latty KS, Burger M, Borrero J, Jovanovic I, Hartig KC. Emission characteristics of bulk aerosols excited by externally focused femtosecond filaments. OPTICS EXPRESS 2023; 31:24652-24666. [PMID: 37475286 DOI: 10.1364/oe.495456] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/26/2023] [Indexed: 07/22/2023]
Abstract
The bulk aerosol emissions excited by externally focused femtosecond laser filaments are characterized using time-resolved plasma imaging and spectroscopy. Images of N2 and N2+ plasma fluorescence are used to characterize the filament dimensions. Emission profiles from bulk Sr aerosols are studied, showing that several localized emission regions in the filament begin to develop for lower repetition rates and higher pulse energies. Plasma temperature and electron density profiles are determined using particle emissions along the length of short- and long-focused filaments, and results are compared for on-axis and side-collected spectra. The use of on-axis collection enables the sampling of light emitted over the entire length of the filament; however, the necessary back-propagation of light makes on-axis collection susceptible to self-absorption as the optical path is extended through the filament plasma column formed in bulk aerosols.
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8
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Rasmussen M, Nagy O, Skupin S, Stathopulos A, Bergé L, Jepsen PU, Zhou B. Frequency-resolved characterization of broadband two-color air-plasma terahertz beam profiles. OPTICS EXPRESS 2023; 31:9287-9298. [PMID: 37157501 DOI: 10.1364/oe.482995] [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
The frequency-resolved terahertz (THz) beam profile characteristics of a two-color air-plasma THz source were investigated in the broadband frequency range (1-15 THz). The frequency resolution is achieved by combining THz waveform measurements and the knife-edge technique. Our results show that the THz focal spot size is strongly frequency dependent. This has important implications on nonlinear THz spectroscopy applications where accurate knowledge of the applied THz electrical field strength onto the sample is important. In addition, the transition between the solid and hollow beam profile of the air-plasma THz beam was carefully identified. Far from the focus, the features across the 1-15 THz range have also been carefully examined, revealing the characteristic conical emission patterns at all frequencies.
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Yamada R, Komatsubara W, Sakurai H, Konishi K, Mio N, Yumoto J, Kuwata-Gonokami M. Simulation of nonlinear propagation of femtosecond laser pulses in air for quantitative prediction of the ablation crater shape. OPTICS EXPRESS 2023; 31:7363-7382. [PMID: 36859869 DOI: 10.1364/oe.482986] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
The utilization of sub-100 fs pulses has attracted attention as an approach to further improve the quality and precision of femtosecond laser microfabrication. However, when using such lasers at pulse energies typical for laser processing, nonlinear propagation effects in air are known to distort the beam's temporal and spatial intensity profile. Due to this distortion, it has been difficult to quantitatively predict the final processed crater shape of materials ablated by such lasers. In this study, we developed a method to quantitatively predict the ablation crater shape, utilizing nonlinear propagation simulations. Investigations revealed that the ablation crater diameters derived by our method were in excellent quantitative agreement with experimental results for several metals over a two-orders-of-magnitude range in the pulse energy. We also found a good quantitative correlation between the simulated central fluence and the ablation depth. Such methods should improve the controllability of laser processing with sub-100 fs pulses and contribute to furthering their practical application to processes over a wide pulse-energy range, including conditions with nonlinear-propagating pulses.
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10
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Vaičaitis V, Balachninaitė O, Matijošius A, Babushkin I, Morgner U. Direct time-resolved plasma characterization with broadband terahertz light pulses. Phys Rev E 2023; 107:015201. [PMID: 36797931 DOI: 10.1103/physreve.107.015201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/23/2022] [Indexed: 01/05/2023]
Abstract
We report here the results of comprehensive plasma characterization and diagnostics by analyzing time-resolved absorption spectra of short ultrabroadband (0.1-50 THz) pulses propagated through the test plasma. Spectral analysis of plasma-induced absorption of such THz pulses provides very direct, in situ, high dynamical range, potentially single-shot access to the plasma density, plasma decay time, electron temperature, and ballistic dynamics of the plasma expansion. We have demonstrated a proof-of-principle measurement of plasma created by an intense laser beam. In particular, we showed a reliable measurement of plasma densities from around 10^{16} to 10^{20}cm^{-3}. Apart from the plasma parameters, this method allowed us to reconstruct peak intensity inside the plasma spot and to observe a very early stage of plasma evolution after its excitation.
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Affiliation(s)
- Virgilijus Vaičaitis
- Laser Research Center, Vilnius University, Saulėtekio 10, Vilnius LT-10223, Lithuania
| | - Ona Balachninaitė
- Laser Research Center, Vilnius University, Saulėtekio 10, Vilnius LT-10223, Lithuania
| | - Aidas Matijošius
- Laser Research Center, Vilnius University, Saulėtekio 10, Vilnius LT-10223, Lithuania
| | - Ihar Babushkin
- Institute of Quantum Optics, Leibniz University Hannover, Welfengarten 1, 30167 Hannover, Germany.,Max Born Institute, Max-Born-Strasse 2a, Berlin 10117, 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 Hannover, Welfengarten 1, 30167 Hannover, Germany.,Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering - Innovation Across Disciplines), Welfengarten 1, 30167 Hannover, Germany
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11
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Rizaev GE, Seleznev LV, Mokrousova DV, Pushkarev DV, Ionin AA. Terahertz emission pattern from a single-color filament plasma. OPTICS LETTERS 2022; 47:5917-5920. [PMID: 37219136 DOI: 10.1364/ol.476382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 10/23/2022] [Indexed: 05/24/2023]
Abstract
We study the angular distribution of different spectral components of the terahertz emission from a single-color laser filament plasma. The opening angle of a terahertz cone is experimentally demonstrated to be proportional to the inverse square root of both plasma channel length and terahertz frequency in the non-linear focusing mode, whereas in the case of linear focusing this dependence breaks down. We also experimentally show that any conclusions of terahertz radiation spectral composition require the angle range from which it is collected to be specified.
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12
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Qi P, Qian W, Guo L, Xue J, Zhang N, Wang Y, Zhang Z, Zhang Z, Lin L, Sun C, Zhu L, Liu W. Sensing with Femtosecond Laser Filamentation. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22187076. [PMID: 36146424 PMCID: PMC9504994 DOI: 10.3390/s22187076] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 05/25/2023]
Abstract
Femtosecond laser filamentation is a unique nonlinear optical phenomenon when high-power ultrafast laser propagation in all transparent optical media. During filamentation in the atmosphere, the ultrastrong field of 1013-1014 W/cm2 with a large distance ranging from meter to kilometers can effectively ionize, break, and excite the molecules and fragments, resulting in characteristic fingerprint emissions, which provide a great opportunity for investigating strong-field molecules interaction in complicated environments, especially remote sensing. Additionally, the ultrastrong intensity inside the filament can damage almost all the detectors and ignite various intricate higher order nonlinear optical effects. These extreme physical conditions and complicated phenomena make the sensing and controlling of filamentation challenging. This paper mainly focuses on recent research advances in sensing with femtosecond laser filamentation, including fundamental physics, sensing and manipulating methods, typical filament-based sensing techniques and application scenarios, opportunities, and challenges toward the filament-based remote sensing under different complicated conditions.
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Affiliation(s)
- Pengfei Qi
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Wenqi Qian
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Lanjun Guo
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Jiayun Xue
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Nan Zhang
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Yuezheng Wang
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Zhi Zhang
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China
| | - Zeliang Zhang
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Lie Lin
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China
| | - Changlin Sun
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
| | - Liguo Zhu
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
| | - Weiwei Liu
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China
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13
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Rastegari A, Diels JC, Kamer B, Liu LR, Arissian L. Measurement of delayed fluorescence in N 2 + with a streak camera. OPTICS EXPRESS 2022; 30:31498-31508. [PMID: 36242229 DOI: 10.1364/oe.468835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/03/2022] [Indexed: 06/16/2023]
Abstract
Using a streak camera, we directly measure time- and space-resolved dynamics of N 2 + emission from a self-seeded filament. Fluorescence emission does not start with ionization, but with a delay in the tenth of ps range.
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14
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Tang H, Men T, Liu X, Hu Y, Su J, Zuo Y, Li P, Liang J, Downer MC, Li Z. Single-shot compressed optical field topography. LIGHT, SCIENCE & APPLICATIONS 2022; 11:244. [PMID: 35915072 PMCID: PMC9343635 DOI: 10.1038/s41377-022-00935-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 07/12/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Femtosecond lasers are powerful in studying matter's ultrafast dynamics within femtosecond to attosecond time scales. Drawing a three-dimensional (3D) topological map of the optical field of a femtosecond laser pulse including its spatiotemporal amplitude and phase distributions, allows one to predict and understand the underlying physics of light interaction with matter, whose spatially resolved transient dielectric function experiences ultrafast evolution. However, such a task is technically challenging for two reasons: first, one has to capture in single-shot and squeeze the 3D information of an optical field profile into a two-dimensional (2D) detector; second, typical detectors are only sensitive to intensity or amplitude information rather than phase. Here we have demonstrated compressed optical field topography (COFT) drawing a 3D map for an ultrafast optical field in single-shot, by combining the coded aperture snapshot spectral imaging (CASSI) technique with a global 3D phase retrieval procedure. COFT can, in single-shot, fully characterize the spatiotemporal coupling of a femtosecond laser pulse, and live stream the light-speed propagation of an air plasma ionization front, unveiling its potential applications in ultrafast sciences.
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Affiliation(s)
- Haocheng Tang
- School of Optical and Electronic Information & Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ting Men
- School of Optical and Electronic Information & Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xianglei Liu
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, Université du Québec, Varennes, Québec, Canada
| | - Yaodan Hu
- School of Optical and Electronic Information & Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jingqin Su
- Laser Fusion Research Center, Chinese Academy of Engineering Physics, Mianyang, Sichuan, China
| | - Yanlei Zuo
- Laser Fusion Research Center, Chinese Academy of Engineering Physics, Mianyang, Sichuan, China
| | - Ping Li
- Laser Fusion Research Center, Chinese Academy of Engineering Physics, Mianyang, Sichuan, China
| | - Jinyang Liang
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, Université du Québec, Varennes, Québec, Canada
| | - Michael C Downer
- Department of Physics, University of Texas at Austin, Austin, TX, USA
| | - Zhengyan Li
- School of Optical and Electronic Information & Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, China.
- Optics Valley Laboratory, Wuhan, Hubei, China.
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15
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Abstract
We experimentally investigate the low-frequency (below 1 THz) spectral content of broadband terahertz (THz) emission from two-color femtosecond filament formed by the 2.7-mJ, 40-fs, 800+400-nm pulse focused into air. For incoherent detection, we screened the Golay cell by the bandpass filters and measured the THz angular distributions at the selected frequencies ν=0.5, 1, 2 and 3 THz. The measured distributions of THz fluence were integrated over the forward hemisphere taking into account the transmittance of the filters, thus providing the estimation of spectral power at the frequencies studied. The spectral power decreases monotonically with the frequency increasing from 0.5 to 3 THz, thus showing that the maximum of THz spectrum is attained at ν≤0.5 THz. The THz waveform measured by electro-optical sampling (EOS) based on ZnTe crystal and transformed into the spectral domain shows that there exists the local maximum of the THz spectral power at ν≈1 THz. This disagrees with monotonic decrease of THz spectral power obtained from the filter-based measurements. We have introduced the correction to the spectral power reconstructed from EOS measurements. This correction takes into account different focal spot size for different THz frequencies contained in the broadband electromagnetic pulse. The corrected EOS spectral power is in semi-quantitative agreement with the one measured by a set of filters.
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16
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Skrodzki PJ, Burger M, Finney LA, Nawara R, Nees J, Jovanovic I. Millisecond-long suppression of spectroscopic optical signals using laser filamentation. OPTICS LETTERS 2021; 46:3777-3780. [PMID: 34329279 DOI: 10.1364/ol.430809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Ultrashort laser pulse filamentation in air can extend the delivery of focused laser energy to distances greatly exceeding the Rayleigh length. In this way, remote measurements can be conducted using many standard methods of analytical spectroscopy. The performance of spectroscopic techniques can be enhanced by temporal gating, which rejects the unwanted noise and background. In the present work, we investigate the thermal relaxation of air in the wake of single-filament plasmas using shadowgraphy. We demonstrate that the transient change in refractive index associated with relaxation of the gas can be used to reject both continuous and time-varying spectroscopic signals, including emission from laser-produced plasmas. This method can augment temporal gating of simple optical detectors.
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17
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Zhang L, Liu J, Gong W, Jiang H, Liu S. Diffraction based single pulse measurement of air ionization dynamics induced by femtosecond laser. OPTICS EXPRESS 2021; 29:18601-18610. [PMID: 34154113 DOI: 10.1364/oe.427364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/26/2021] [Indexed: 06/13/2023]
Abstract
A single pulse diffraction method to probe the plasma column evolution of the air ionization induced by the femtosecond laser pulse has been proposed. By utilizing a linearly chirped pulse as the probe light, the spatiotemporal evolution spectrum of the plasma column can be acquired in a single measurement. A method based on the Fresnel diffraction integral is proposed to extract the evolution of the phase shift after the probe light is crossing through the plasma column. Results show that the plasma expands rapidly within 7 ps due to the ionization, and then reaches a steady state with a diameter of about 80 μm with the pump pulse energy of 1 mJ. Furtherly, the temporal profile of the free electron density and the refractive index in the plasma region were determined using the corresponding physical models. The single-shot method can be expected to broaden the way for detecting the dynamics of the femtosecond laser-induced plasma.
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18
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Sheng W, Tang F, Zhang Z, Chen Y, Peng XY, Sheng ZM. Spectral control of terahertz radiation from inhomogeneous plasma filaments by tailoring two-color laser beams. OPTICS EXPRESS 2021; 29:8676-8684. [PMID: 33820310 DOI: 10.1364/oe.417515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/07/2021] [Indexed: 06/12/2023]
Abstract
Terahertz (THz) radiation from an inhomogeneous plasma filament generated by focusing two-color femtosecond laser pulses into argon gas filled in a chamber is investigated experimentally by tailoring the Gaussian pump laser beams with an iris, where broadband THz emission over 10 THz is produced. It is found that the collected far-field THz radiation includes not only coherent but also partial-coherent components of the THz waves, which are emitted from the different parts of the inhomogeneous plasma filament with different plasma densities, contributing correspondingly to the different frequencies of the THz spectrum. Our results suggest that the THz spectrum can be manipulated by controlling the plasma density distribution of the filaments.
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19
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Zang H, Li H, Zhang W, Fu Y, Chen S, Xu H, Li R. Robust and ultralow-energy-threshold ignition of a lean mixture by an ultrashort-pulsed laser in the filamentation regime. LIGHT, SCIENCE & APPLICATIONS 2021; 10:49. [PMID: 33674550 PMCID: PMC7935939 DOI: 10.1038/s41377-021-00496-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 05/31/2023]
Abstract
Laser ignition (LI) allows for precise manipulation of ignition timing and location and is promising for green combustion of automobile and rocket engines and aero-turbines under lean-fuel conditions with improved emission efficiency; however, achieving completely effective and reliable ignition is still a challenge. Here, we report the realization of igniting a lean methane/air mixture with a 100% success rate by an ultrashort femtosecond laser, which has long been regarded as an unsuitable fuel ignition source. We demonstrate that the minimum ignition energy can decrease to the sub-mJ level depending on the laser filamentation formation, and reveal that the resultant early OH radical yield significantly increases as the laser energy reaches the ignition threshold, showing a clear boundary for misfire and fire cases. Potential mechanisms for robust ultrashort LI are the filamentation-induced heating effect followed by exothermal chemical reactions, in combination with the line ignition effect along the filament. Our results pave the way toward robust and efficient ignition of lean-fuel engines by ultrashort-pulsed lasers.
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Affiliation(s)
- Hongwei Zang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 130012, Changchun, China
| | - Helong Li
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 130012, Changchun, China
- Institute of Atomic and Molecular Physics, Jilin University, 130012, Changchun, China
| | - Wei Zhang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 130012, Changchun, China
| | - Yao Fu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 130012, Changchun, China
| | - Shanming Chen
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 130012, Changchun, China
| | - Huailiang Xu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 130012, Changchun, China.
- CAS Center for Excellence in Ultra-intense Laser Science, 201800, Shanghai, China.
| | - Ruxin Li
- CAS Center for Excellence in Ultra-intense Laser Science, 201800, Shanghai, China.
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, 201800, Shanghai, China.
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China.
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20
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Zyatikov IA, Losev VF, Lubenko DM, Sandabkin EA. Analysis of the active medium parameters of molecular nitrogen ions in ambient air. OPTICS LETTERS 2020; 45:6518-6521. [PMID: 33258851 DOI: 10.1364/ol.403577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/13/2020] [Indexed: 06/12/2023]
Abstract
In this Letter, we report the direct streak camera measurements of the duration of a lasing pulse from molecular nitrogen ions under various focusing conditions of 10 mJ, 950 nm femtosecond pump pulse in atmospheric pressure air. The parameters of the active medium are analyzed, and a mechanism for formation of picosecond lasing pulse duration at femtosecond seed pulse duration is proposed.
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21
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Zhang Z, Dai Z, Wang Y, Chu C, Su Q, Kosareva O, Zhang N, Lin L, Liu W. Fabricating THz spiral zone plate by high throughput femtosecond laser air filament direct writing. Sci Rep 2020; 10:13965. [PMID: 32811898 PMCID: PMC7434771 DOI: 10.1038/s41598-020-70997-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/04/2020] [Indexed: 11/09/2022] Open
Abstract
The sixth-generation wireless communication will exploit the radio band with frequencies higher than 90 GHz, reaching terahertz (THz) band, to achieve huge signal bandwidths. However, the cost-effective fabrication methods of the key components in THz band, which can compromise large scale, high precision, and high efficiency, remain great challenges at present. In this work, we have developed a high throughput fabrication method based on the femtosecond laser filament direct writing. The ability of fabricating large-scale THz elements with high precision and fast speed has been demonstrated by fabricating 100 × 100 mm2 spiral zone plates (SZPs), which can convert the Gaussian THz beam into vortex beam. The performance of the obtained THz vortex beam is in good agreement with the theoretical predictions. The fabrication method reported here has promising applications in fabricating various kinds of THz elements on substrates with both flat and curved surfaces.
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Affiliation(s)
- Zhi Zhang
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China
| | - Zijie Dai
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China
| | - Yunfei Wang
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China
| | - Chunyue Chu
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China
| | - Qiang Su
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China
| | - Olga Kosareva
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China.,International Laser Center, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Nan Zhang
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China.
| | - Lie Lin
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China
| | - Weiwei Liu
- Institute of Modern Optics, Nankai University, Tianjin, 300350, China.
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22
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Koribut AV, Rizaev GE, Mokrousova DV, Savinov SA, Reutov AA, Mityagin YA, Seleznev LV, Ionin AA. Similarity of angular distribution for THz radiation emitted by laser filament plasma channels of different lengths. OPTICS LETTERS 2020; 45:4009-4011. [PMID: 32667341 DOI: 10.1364/ol.394377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
The influence of plasma channel length on an angular terahertz (THz) radiation distribution is experimentally studied for the channel formed under filamentation of an ultrashort laser pulse. It is shown that the angular distribution of the THz emission depends only on laser intensity in the filament and plasma density of the plasma channel and does not depend on the plasma channel length. A qualitative explanation of the THz emission screening by the filament plasma channel is proposed.
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23
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Thul D, Richardson M, Rostami Fairchild S. Spatially resolved filament wavefront dynamics. Sci Rep 2020; 10:8920. [PMID: 32488107 PMCID: PMC7265553 DOI: 10.1038/s41598-020-65431-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 04/14/2020] [Indexed: 11/09/2022] Open
Abstract
Spatially resolved wavefront measurements are presented during nonlinear self-collapse and provide the first detailed characterization of wavefront evolution during filament formation. The wavefront dynamics of key nonlinear processes including Kerr self-focusing, ionization and plasma defocusing, and dynamic spatial replenishment are identified and resolved in both the filament core and reservoir regions. These results are analyzed and interpreted with respect to numerical simulations and provide insight into fundamental aspects of filamentation. They also inform applications based on phase manipulation, such as external beam guiding, and present a new method for measuring the nonlinear index of refraction, n2.
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Affiliation(s)
- Daniel Thul
- Laser Plasma Laboratory, College of Optics and Photonics, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL, 32816, USA
| | - Martin Richardson
- Laser Plasma Laboratory, College of Optics and Photonics, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL, 32816, USA.,Department of Physics and Space Sciences, Florida Institute of Technology, 3012 Engineering St, Melbourne, FL, 32901, USA
| | - Shermineh Rostami Fairchild
- Laser Plasma Laboratory, College of Optics and Photonics, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL, 32816, USA. .,Department of Physics and Space Sciences, Florida Institute of Technology, 3012 Engineering St, Melbourne, FL, 32901, USA.
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24
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Guo H, Wang TJ, Zhang X, Liu C, Chen N, Liu Y, Sun H, Shen B, Jin Y, Leng Y, Li R. Direct measurement of radial fluence distribution inside a femtosecond laser filament core. OPTICS EXPRESS 2020; 28:15529-15541. [PMID: 32403579 DOI: 10.1364/oe.392827] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
Modulation and direct measurement of the radial fluence distribution inside a single filament core (especially less than 100 μm in diameter) is crucial to filament-based applications. We report direct measurements of the radial fluence distribution inside a femtosecond laser filament core and its evolution via the filament-induced ablation method. The radial fluence distributions were modulated by manipulating the input pulse diffraction through an iris. Compared with using a traditionally circular iris, a stellate iris substantially suppressed the diffraction effect, and laser fluence, intensity and plasma density inside the filament core were considerably increased. The radial fluence inside filament cores was also quantitatively measured via the filament drilling diaphragms approach. Furthermore, numerical simulations were performed to support the experimental results by solving nonlinear Schrödinger equations. The effects of the tooth size of the stellate iris were numerically investigated, which indicated that bigger tooth favors higher fluence and longer filament. In addition to being beneficial in understanding the filamentation process and its control, the results of this study can also be valuable for filament-based applications.
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25
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Danylo R, Zhang X, Fan Z, Zhou D, Lu Q, Zhou B, Liang Q, Zhuang S, Houard A, Mysyrowicz A, Oliva E, Liu Y. Formation Dynamics of Excited Neutral Nitrogen Molecules inside Femtosecond Laser Filaments. PHYSICAL REVIEW LETTERS 2019; 123:243203. [PMID: 31922877 DOI: 10.1103/physrevlett.123.243203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Nitrogen molecules are promoted to excited neutral states during femtosecond laser pulse filamentary propagation in atmosphere, leading to a characteristic UV fluorescence. Using a laser-induced fluorescence depletion technique, we measure the formation dynamics of these excited neutral nitrogen molecules with femtosecond time resolution. We find that the excited neutral molecules are formed in an unexpected ultrafast timescale of ∼4 ps at 1 bar and ∼120 ps at 30 mbar pressure. From this observation we deduce that the excitation of neutral N_{2} occurs via multiple collisions with hot free electrons. Numerical simulations based on rate equations reproduce well this ultrafast formation time and its dependence on gas pressure, and thus support this interpretation.
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Affiliation(s)
- Rostyslav Danylo
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
| | - Xiang Zhang
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
| | - Zhengquan Fan
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
| | - Dongjie Zhou
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
| | - Qi Lu
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
| | - Bin Zhou
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
| | - Qingqing Liang
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
| | - Songlin Zhuang
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
| | - Aurélien Houard
- Laboratoire d'Optique Appliquée, ENSTA Paris, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, 828 Boulevard des Maréchaux, 91762 Palaiseau cedex, France
| | - André Mysyrowicz
- Laboratoire d'Optique Appliquée, ENSTA Paris, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, 828 Boulevard des Maréchaux, 91762 Palaiseau cedex, France
| | - Eduardo Oliva
- Departamento de Ingeniería Energética, ETSI Industriales, Universidad Politécnica de Madrid, E-28006 Madrid, Spain
- Instituto de Fusión Nuclear "Guillermo Velarde", Universidad Politécnica de Madrid, 28006 Madrid, Spain
| | - Yi Liu
- Engineering Research Center of Optical Instrument and System, The Ministry of Education; Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 516, Jungong Road, 200093 Shanghai, China
- Laboratoire d'Optique Appliquée, ENSTA Paris, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, 828 Boulevard des Maréchaux, 91762 Palaiseau cedex, France
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26
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Gao X, Patwardhan G, Shim B, Gaeta AL. Ionization-assisted refocusing of femtosecond Gaussian beams. OPTICS LETTERS 2019; 44:5888-5891. [PMID: 31774805 DOI: 10.1364/ol.44.005888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 10/31/2019] [Indexed: 06/10/2023]
Abstract
Ionization occurs ubiquitously in intense laser-matter interaction and often leads to rapid decrease in laser intensity via plasma defocusing, shortening the effective interaction length of desired high-field processes. Refocusing of pulses may compensate for this adverse effect. However, it typically relies on Kerr-induced self-focusing and requires sufficiently high power. Here, we present simulations showing the refocusing of intense pulses with an initial Gaussian beam profile in atmospheric pressure gases at relatively low power. We attribute this refocusing to the formation of ring-structure plasmas. We find that tighter focusing leads to stronger refocusing, and the initial chirp of the pulse greatly affects its dynamics due to spatiotemporal coupling of focused broadband pulses. Our results highlight a novel aspect of complex pulse dynamics and can be relevant to applications involving tightly focused ultrafast Gaussian beams.
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27
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Thul D, Fairchild SR, Richardson M. Direct wavefront measurements of filaments in the assisted-collapse regime. OPTICS EXPRESS 2019; 27:21253-21263. [PMID: 31510205 DOI: 10.1364/oe.27.021253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 06/23/2019] [Indexed: 06/10/2023]
Abstract
Wavefront measurements are used to characterize the process of filament formation in air under assisted-collapse conditions. Direct wavefront evolution within the filament, measured for the first time, is used to characterize the role of energy reservoir in filament formation. This information provides new insights into the filament process and phase sensitive applications such as engineered plasma waveguides.
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28
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A Review of Femtosecond Laser-Induced Emission Techniques for Combustion and Flow Field Diagnostics. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9091906] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The applications of femtosecond lasers to the diagnostics of combustion and flow field have recently attracted increasing interest. Many novel spectroscopic methods have been developed in obtaining non-intrusive measurements of temperature, velocity, and species concentrations with unprecedented possibilities. In this paper, several applications of femtosecond-laser-based incoherent techniques in the field of combustion diagnostics were reviewed, including two-photon femtosecond laser-induced fluorescence (fs-TPLIF), femtosecond laser-induced breakdown spectroscopy (fs-LIBS), filament-induced nonlinear spectroscopy (FINS), femtosecond laser-induced plasma spectroscopy (FLIPS), femtosecond laser electronic excitation tagging velocimetry (FLEET), femtosecond laser-induced cyano chemiluminescence (FLICC), and filamentary anemometry using femtosecond laser-extended electric discharge (FALED). Furthermore, prospects of the femtosecond-laser-based combustion diagnostic techniques in the future were analyzed and discussed to provide a reference for the relevant researchers.
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29
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Burger M, Skrodzki PJ, Nees J, Jovanovic I. Electrical conductance of near-infrared femtosecond air filaments in the multi-filament regime. OPTICS LETTERS 2018; 43:5520-5523. [PMID: 30439885 DOI: 10.1364/ol.43.005520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/11/2018] [Indexed: 06/09/2023]
Abstract
Electrical conductive properties of femtosecond laser filaments are of significant interest for applications such as remote arc suppression and discharge guiding. We transmitted electrical current through a DC-biased air plasma channel formed in the wake of an energetic femtosecond laser pulse and observed an increased rate of change of the charge transmitted through the ionized channel with laser energy when crossing from the single- to multi-filament regimes. This behavior is attributed to the confluent effects of greater electron density and an increased cross-sectional area of the multi-filament plasma structures. As the laser energy is increased, the formation of additional conductive channels in the multi-filamentation regime becomes a significant contributor to the rapid increase of conductivity. These observations suggest a potential path to attractive applications such as efficient energy transfer in air mediated by femtosecond laser-produced filaments.
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30
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Sun H, Liu Y, Liu J, Su Z, Ju J, Hu X, Wang C, Wang T, Chin SL, Li R, Xu Z. Femtosecond laser filament-assisted AgI-type pyrotechnic nucleant-induced water condensation in cloud chamber. OPTICS EXPRESS 2018; 26:29687-29699. [PMID: 30469930 DOI: 10.1364/oe.26.029687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 10/23/2018] [Indexed: 06/09/2023]
Abstract
AgI-type pyrotechnics are widely used in the field of weather modification, as a kind of artificial ice nuclei. However, their precipitation yield remains an intensively studied area. In this paper, we present a study of AgI-type pyrotechnic nucleant-induced water condensation promoted by femtosecond laser filaments in a cloud chamber. It is found that when 50-ml sample was irradiated by the laser filaments, the particles condensed on the glass slide are more soluble and slightly larger (5-15 μm). The irradiation of the laser filament on the nucleant rarely induces the generation of particles of sizes larger than 1 μm; however, it increases the decay time of particles from 13 to 18 min by the creation of numerous small particles. The amount of snow on the cold bottom plate increases by 4.2-13.1% in 2 h, compared to that without the irradiation of the laser filament. These results are associated with the production of high-concentration HNO3 by the laser filament. The concentration of HNO3 in the melt water increases by more than ten times when the sample was irradiated by the laser filaments.
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31
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Finney LA, Skrodzki PJ, Burger M, Xiao X, Nees J, Jovanovic I. Optical emission from ultrafast laser filament-produced air plasmas in the multiple filament regime. OPTICS EXPRESS 2018; 26:29110-29122. [PMID: 30470078 DOI: 10.1364/oe.26.029110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 09/22/2018] [Indexed: 06/09/2023]
Abstract
We perform optical emission spectroscopy of ultrafast laser filament-produced air plasmas in the multiple filament regime at driving wavelengths of 400 nm and 800 nm. The spatiotemporal structure of the emission from the plasmas are observed and the emission spectra are used to estimate plasma temperature and density for a range of laser parameters. Plasma temperatures are determined from the molecular nitrogen fluorescence, while the electron densities are estimated from Stark broadening of the oxygen-I 777.19-nm line. Electron temperatures are determined to be in the range of 5000-5200 K and they do not vary significantly along the length of the filament, nor are they sensitive to incident laser energy or wavelength. Electron densities are on order of 1016 cm-3 and show a greater variation with axial position, laser energy, and laser wavelength. We discuss mechanisms responsible for spatial localization of emitting species within the filament. Optical emission spectroscopy offers a simple, non-perturbing method to measure filament properties, that allows the information on the associated molecular transitions and excitation/ionization mechanisms to be extracted.
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32
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Hou H, Yang B, Mao X, Zorba V, Ran P, Russo RE. Characteristics of plasma plume in ultrafast laser ablation with a weakly ionized air channel. OPTICS EXPRESS 2018; 26:13425-13435. [PMID: 29801368 DOI: 10.1364/oe.26.013425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/01/2018] [Indexed: 06/08/2023]
Abstract
We report the influence of femtosecond (fs) laser weakly ionized air channel on characteristics of plasma induced from fs-laser ablation of solid Zr metal target. A novel method to create high temperature, low electron density plasma with intense elemental emission and weak bremsstrahlung emission was demonstrated. Weakly ionized air channel was generated as a result of a non-linear phenomenon. Two-dimensional time-resolved optical-emission images of plasma plumes were taken for plume dynamics analysis. Dynamic physical properties of filament channels were simulated. In particular, we investigated the influence of weakly ionized air channel on the evolution of solid plasma plume. Plasma plume splitting was observed whilst longer weakly ionized air channel formed above the ablation spot. The domination mechanism for splitting is attributed to the long-lived underdense channel created by fs-laser induced weakly ionization of air. The evolutions of atomic/molecular emission intensity, peak broadening, and plasma temperature were analyzed, and the results show that the part of plasma entering weakly ionized air channel features higher initial temperature, lower electron density and faster decay.
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33
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Shumakova V, Ališauskas S, Malevich P, Gollner C, Baltuška A, Kartashov D, Zheltikov AM, Mitrofanov AV, Voronin AA, Sidorov-Biryukov DA, Pugžlys A. Filamentation of mid-IR pulses in ambient air in the vicinity of molecular resonances. OPTICS LETTERS 2018; 43:2185-2188. [PMID: 29714785 DOI: 10.1364/ol.43.002185] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 02/26/2018] [Indexed: 06/08/2023]
Abstract
Properties of filaments ignited by multi-millijoule, 90 fs mid-infrared pulses centered at 3.9 μm are examined experimentally by monitoring plasma density, losses, spectral dynamics and beam profile evolution at different focusing strengths. By changing from strong (f=0.25 m) to loose (f=7 m) focusing, we observe a shift from plasma-assisted filamentation to filaments with low plasma density. In the latter case, filamentation manifests itself by beam self-symmetrization and spatial self-channeling. Spectral dynamics in the case of loose focusing is dominated by the nonlinear Raman frequency downshift, which leads to the overlap with the CO2 resonance in the vicinity of 4.2 μm. The dynamic CO2 absorption in the case of 3.9 μm filaments with their low plasma content is the main mechanism of energy losses and, either alone or together with other nonlinear processes, contributes to the arrest of intensity.
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34
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Li H, Zang H, Huang Q, Liu C, Su Y, Fu Y, Hou M, Li A, Chen H, Chin SL, Xu H. Polarization-orthogonal filament array induced by birefringent crystals in air. OPTICS EXPRESS 2018; 26:8515-8521. [PMID: 29715817 DOI: 10.1364/oe.26.008515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/20/2018] [Indexed: 06/08/2023]
Abstract
We demonstrate the generation of filament array with orthogonal polarizations in air by using specifically designed wedge-type birefringent quartz plates. Experimental results show that the number of the generated filaments can be expressed as N = 2n wherenis the number of quartz plates inserted in the laser propagation path. By manipulating the optic axis of the quartz plates with respect to the polarization direction of the input laser pulse, the generated filaments can be separated into two parts with the polarization directions perpendicular with each other. The separation distance between the adjacent filaments is found to be linearly dependent on the focal length of external focusing lens. Our results provide a simple and efficient way to generate regular and reproductive femtosecond filament array in air.
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35
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Hah J, Jiang W, He ZH, Nees JA, Hou B, Thomas AGR, Krushelnick K. Enhancement of THz generation by feedback-optimized wavefront manipulation. OPTICS EXPRESS 2017; 25:17271-17279. [PMID: 28789220 DOI: 10.1364/oe.25.017271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 05/25/2017] [Indexed: 06/07/2023]
Abstract
We apply active feedback optimization methods to pyroelectric measurements of a THz signal generated by four wave mixing in air using 1 mJ to 12 mJ, 35 fs laser pulses operating at 12 kHz repetition rate. A genetic algorithm, using the THz signal as a figure of merit, determines the voltage settings to a deformable mirror and results in up to a 6 fold improvement in the THz signal compared with settings optimized for the best focus. It is possible to optimize for different THz generation processes using this technique.
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36
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Tan C, Fu X, Hu Y, Deng Y, Shi X, Zhan S, Xi Z. Plasma optical modulation for lasers based on the plasma induced by femtosecond pulses. OPTICS EXPRESS 2017; 25:14065-14076. [PMID: 28788992 DOI: 10.1364/oe.25.014065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/01/2017] [Indexed: 06/07/2023]
Abstract
We present a theoretical and experimental study of plasma optical modulation for probe lasers based on the plasma induced by pump pulses. This concept relies on two co-propagating laser pulses in carbon disulfide, where a drive laser pulse first excites plasma channels while a following carrier laser pulse is modulated by the plasma. The modulation on the probe beam can be conveniently adjusted through electron density, plasma width, propagation distance of plasma, the power of pump lasers, or the pump beam's profile. The experimental results and theoretical solutions are very consistent, which fully illustrates that this method for plasma optical modulation is reasonable. This pump-probe method is also a potential measurement technique for inferring the on-axis plasma density shape.
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37
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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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38
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Liu Y, Wang T, Chen N, Du S, Ju J, Sun H, Wang C, Liu J, Lu H, Chin SL, Li R, Xu Z, Wang Z. Probing the effective length of plasma inside a filament. OPTICS EXPRESS 2017; 25:11078-11087. [PMID: 28788791 DOI: 10.1364/oe.25.011078] [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 present a novel method based on plasma-guided corona discharges to probe the plasma density longitudinal distribution, which is particularly good for the weakly ionized plasmas (~1014 cm-3). With this method, plasma density longitudinal distribution inside both a weakly ionized plasma and a filament were characterized. When a high voltage electric field was applied onto a plasma channel, the original ionization created by a laser pulse would be enhanced and streamer coronas formed along the channel. By measuring the fluorescence of enhanced ionization, in particular, on both ends of a filament, the weak otherwise invisible plasma regions created by the laser pulse were identified. The observed plasma guided coronas were qualitatively understood by solving a 3D Maxwell equation through finite element analysis. The technique paves a new way to probe low density plasma and to precisely measure the effective length of plasma inside a filament.
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39
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Characteristics and Applications of Spatiotemporally Focused Femtosecond Laser Pulses. APPLIED SCIENCES-BASEL 2016. [DOI: 10.3390/app6120428] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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40
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Li H, Jiang Y, Li S, Chen A, Li S, Jin M. Research on the fluorescence emission from water vapor induced by femtosecond filamentation in air. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.09.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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41
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Sun H, Liu Y, Ju J, Tian Y, Bai Y, Liu Y, Du S, Wang C, Wang T, Liu J, Chin SL, Li R, Xu Z. Picosecond laser-induced water condensation in a cloud chamber. OPTICS EXPRESS 2016; 24:20494-20506. [PMID: 27607654 DOI: 10.1364/oe.24.020494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigated water condensation in a laboratory cloud chamber induced by picosecond (ps) laser pulses at ~350 ps (800 nm/1-1000 Hz) with a maximum peak power of ~25 MW. The peak power was much lower than the critical power for self-focusing in air (~3-10 GW depending on the pulse duration). Sparks, airflow and snow formation were observed under different laser energies or repetition rates. It was found that weaker ps laser pulses can also induce water condensation by exploding and breaking down ice crystals and/or water droplets into tiny particles although there was no formation of laser filament. These tiny particles would grow until precipitation in a super-saturation zone due to laser-induced airflow in a cold region with a large temperature gradient.
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42
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Dharmadhikari JA, Dharmadhikari AK, Kasuba KC, Bharambe H, D'Souza JS, Rathod KD, Mathur D. Optical control of filamentation-induced damage to DNA by intense, ultrashort, near-infrared laser pulses. Sci Rep 2016; 6:27515. [PMID: 27279565 PMCID: PMC4899723 DOI: 10.1038/srep27515] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 05/20/2016] [Indexed: 11/09/2022] Open
Abstract
We report on damage to DNA in an aqueous medium induced by ultrashort pulses of intense laser light of 800 nm wavelength. Focusing of such pulses, using lenses of various focal lengths, induces plasma formation within the aqueous medium. Such plasma can have a spatial extent that is far in excess of the Rayleigh range. In the case of water, the resulting ionization and dissociation gives rise to in situ generation of low-energy electrons and OH-radicals. Interactions of these with plasmid DNA produce nicks in the DNA backbone: single strand breaks (SSBs) are induced as are, at higher laser intensities, double strand breaks (DSBs). Under physiological conditions, the latter are not readily amenable to repair. Systematic quantification of SSBs and DSBs at different values of incident laser energy and under different external focusing conditions reveals that damage occurs in two distinct regimes. Numerical aperture is the experimental handle that delineates the two regimes, permitting simple optical control over the extent of DNA damage.
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Affiliation(s)
- J A Dharmadhikari
- Centre for Atomic and Molecular Physics, Manipal University, Manipal 576 104, India
| | - A K Dharmadhikari
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005, India
| | - K C Kasuba
- UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (East), Mumbai 400 098, India
| | - H Bharambe
- UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (East), Mumbai 400 098, India
| | - J S D'Souza
- UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (East), Mumbai 400 098, India
| | - K D Rathod
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005, India
| | - D Mathur
- Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005, India
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43
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Liu Y, Sun H, Liu J, Liang H, Ju J, Wang T, Tian Y, Wang C, Liu Y, Chin SL, Li R. Laser-filamentation-induced water condensation and snow formation in a cloud chamber filled with different ambient gases. OPTICS EXPRESS 2016; 24:7364-7373. [PMID: 27137026 DOI: 10.1364/oe.24.007364] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We investigated femtosecond laser-filamentation-induced airflow, water condensation and snow formation in a cloud chamber filled respectively with air, argon and helium. The mass of snow induced by laser filaments was found being the maximum when the chamber was filled with argon, followed by air and being the minimum with helium. We also discussed the mechanisms of water condensation in different gases. The results show that filaments with higher laser absorption efficiency, which result in higher plasma density, are beneficial for triggering intense airflow and thus more water condensation and precipitation.
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44
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Feng Z, Li W, Yu C, Liu X, Liu Y, Liu J, Fu L. Influence of the external focusing and the pulse parameters on the propagation of femtosecond annular Gaussian filaments in air. OPTICS EXPRESS 2016; 24:6381-6390. [PMID: 27136829 DOI: 10.1364/oe.24.006381] [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
We numerically investigate the effects of the external focusing and the pulse parameters on the propagation of the ring Gaussian filaments in air. The simulation results indicate that the onset distance of filament, the length and uniformity of the plasma strings, and the energy deposition strongly depend on these optical parameters. The length of optical filament can be extended greatly by adjusting the lens parameters near the maximum energy deposition. In addition, we find that, under the same initial intensity, the length and uniformity of the plasma strings can be tuned by increasing the beam width better than increasing the beam radius.
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45
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Point G, Thouin E, Mysyrowicz A, Houard A. Energy deposition from focused terawatt laser pulses in air undergoing multifilamentation. OPTICS EXPRESS 2016; 24:6271-6282. [PMID: 27136820 DOI: 10.1364/oe.24.006271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Laser filamentation is responsible for the deposition of a significant part of the laser pulse energy in the propagation medium. We found that using terawatt laser pulses and moderately strong focusing conditions in air, more than 60 % of the pulses energy is transferred to the medium, eventually degrading into heat. This results in a strong hydrodynamic reaction of air with the generation of shock waves and associated underdense channels for each of the generated multiple filaments. In the focal zone, where filaments are close to each other, these discrete channels eventually merge to form a single cylindrical low-density tube over a ~ 1 µs timescale. We measured the maximum lineic deposited energy to be more than 1 J·m-1.
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46
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Hong Z, Zhang Q, Ali Rezvani S, Lan P, Lu P. Extending plasma channel of filamentation with a multi-focal-length beam. OPTICS EXPRESS 2016; 24:4029-4041. [PMID: 26907055 DOI: 10.1364/oe.24.004029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We propose a novel scheme that lengthens the plasma channel in filamentation with a multi-focal-length beam. Instead of one focal length introduced by a conventional convex lens, the multi-focal-length beam modulated by a spatial light modulator (SLM) produces a filament in an extended range with limited but strictly manipulated laser energy. The results show that the scheme is capable of doubling the filament length compared to a single-lens scheme with a 2-mJ input pulse. The filament location and length can be simply tuned by altering the spatial amplitude and phase or employing higher energies. Furthermore, the extended filament length leads to the generation of a broadened continuum ranging from visible (VIS) to infrared (IR) domain. This versatile scheme offers an efficient tool for the development of a variety of applications involving ultrafast nonlinear optics.
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47
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Li H, Chu W, Zang H, Xu H, Cheng Y, Chin SL. Critical power and clamping intensity inside a filament in a flame. OPTICS EXPRESS 2016; 24:3424-3431. [PMID: 26907001 DOI: 10.1364/oe.24.003424] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report on measurements of both the critical power for self-focusing of a Ti: Sapphire 800 nm femtosecond laser and the peak intensity clamped inside a single filament in an ethanol-air flame on an alcohol burner array. By observing the shift of focal position of femtosecond laser pulses, we determine the critical power in the flame to be 2.2 ± 0.3 GW, which is 4-5 times smaller than the usually quoted one in air. The clamped laser intensity inside the filament is measured to be roughly half of that in air. Our results provide insights into the understanding of femtosecond laser filamentation in flames for practical application of combustion diagnostics.
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48
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Wang TJ, Wei Y, Liu Y, Chen N, Liu Y, Ju J, Sun H, Wang C, Lu H, Liu J, Chin SL, Li R, Xu Z. Direct observation of laser guided corona discharges. Sci Rep 2015; 5:18681. [PMID: 26679271 PMCID: PMC4683528 DOI: 10.1038/srep18681] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/23/2015] [Indexed: 11/09/2022] Open
Abstract
Laser based lightning control holds a promising way to solve the problem of the long standing disaster of lightning strikes. But it is a challenging project due to insufficient understanding of the interaction between laser plasma channel and high voltage electric filed. In this work, a direct observation of laser guided corona discharge is reported. Laser filament guided streamer and leader types of corona discharges were observed. An enhanced ionization took place in the leader (filament) through the interaction with the high voltage discharging field. The fluorescence lifetime of laser filament guided corona discharge was measured to be several microseconds, which is 3 orders of magnitude longer than the fluorescence lifetime of laser filaments. This work could be advantageous towards a better understanding of laser assisted leader development in the atmosphere.
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Affiliation(s)
- Tie-Jun Wang
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Yingxia Wei
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Yaoxiang Liu
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Na Chen
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Yonghong Liu
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Jingjing Ju
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Haiyi Sun
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Cheng Wang
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Haihe Lu
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Jiansheng Liu
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - See Leang Chin
- Centre d'Optique, Photonique et Laser (COPL) and Département de physique, de génie physique et d'optique, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Ruxin Li
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
| | - Zhizhan Xu
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China
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49
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Lu X, Chen SY, Ma JL, Hou L, Liao GQ, Wang JG, Han YJ, Liu XL, Teng H, Han HN, Li YT, Chen LM, Wei ZY, Zhang J. Quasi-steady-state air plasma channel produced by a femtosecond laser pulse sequence. Sci Rep 2015; 5:15515. [PMID: 26493279 PMCID: PMC4616044 DOI: 10.1038/srep15515] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/28/2015] [Indexed: 11/14/2022] Open
Abstract
A long air plasma channel can be formed by filamentation of intense femtosecond laser pulses. However, the lifetime of the plasma channel produced by a single femtosecond laser pulse is too short (only a few nanoseconds) for many potential applications based on the conductivity of the plasma channel. Therefore, prolonging the lifetime of the plasma channel is one of the key challenges in the research of femtosecond laser filamentation. In this study, a unique femtosecond laser source was developed to produce a high-quality femtosecond laser pulse sequence with an interval of 2.9 ns and a uniformly distributed single-pulse energy. The metre scale quasi-steady-state plasma channel with a 60–80 ns lifetime was formed by such pulse sequences in air. The simulation study for filamentation of dual femtosecond pulses indicated that the plasma channel left by the previous pulse was weakly affected the filamentation of the next pulse in sequence under our experimental conditions.
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Affiliation(s)
- Xin Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shi-You Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jing-Long Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Lei Hou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Guo-Qian Liao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jin-Guang Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Jing Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,Department of Physics, Heze University, Heze, 274015, China
| | - Xiao-Long Liu
- Academy of Opto-Electronics, Chinese academy of sciences, Beijing, 100094, China
| | - Hao Teng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hai-Nian Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Tong Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Li-Ming Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhi-Yi Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China.,IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
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50
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Xu H, Lötstedt E, Iwasaki A, Yamanouchi K. Sub-10-fs population inversion in N2(+) in air lasing through multiple state coupling. Nat Commun 2015; 6:8347. [PMID: 26403139 PMCID: PMC4598559 DOI: 10.1038/ncomms9347] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 08/13/2015] [Indexed: 01/01/2023] Open
Abstract
Laser filamentation generated when intense laser pulses propagate in air has been an attractive phenomenon having a variety of potential applications such as detection and spectroscopy of gases at far distant places. It was discovered recently that the filamentation in air induces ‘lasing', showing that electronically excited N2+ is population-inverted, exhibiting marked contrast to the common understanding that molecular ions generated by intense laser fields are prepared mostly in their electronic ground states. Here, to clarify the mechanism of the population inversion, we adopt few-cycle laser pulses, and experimentally demonstrate that the lasing at 391 nm occurs instantaneously after N2+ is produced. Numerical simulations clarify that the population inversion is realized by the post-ionization couplings among the lowest three electronic states of N2+. Our results shed light on the controversy over the mechanism of the air lasing, and show that this post-ionization coupling can be a general mechanism of the atmospheric lasing. Remote generation of population-inverted gain media in air is a step towards the realization of bright and coherent atmospheric lasers. Here, the authors verify population inversion in N2+ and demonstrate the generation of air lasing by acting on it as the gain medium.
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Affiliation(s)
- Huailiang Xu
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Erik Lötstedt
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Atsushi Iwasaki
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kaoru Yamanouchi
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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