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Mei H, Jiang H, Houard A, Tikhonchuk V, Oliva E, Mysyrowicz A, Gong Q, Wu C, Liu Y. Fluorescence and lasing of neutral nitrogen molecules inside femtosecond laser filaments in air: mechanism and applications. Phys Chem Chem Phys 2024; 26:23528-23543. [PMID: 39081061 DOI: 10.1039/d4cp01626b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
High power femtosecond laser pulses launched in air undergo nonlinear filamentary propagation, featuring a bright and thin plasma channel in air with its length much longer than the Rayleigh length of the laser beam. During this nonlinear propagation process, the laser pulses experience rich and complex spatial and temporal transformations. With its applications ranging from supercontinuum generation, laser pulse compression, remote sensing to triggering of lightning, the underlying physical mechanism of filamentation has been intensively studied. In this review, we will focus on the fluorescence and cavity-free lasing effect of the plasma filaments in air. The different mechanisms underlying the fluorescence of the excited neutral nitrogen molecules will be throughly examined and it is concluded that the electron collision excitation is the dominant channel for the formation of the excited nitrogen molecules. The recently discovered "air lasing" effect, a cavity-free bidirectional lasing emission emitted by the filaments, will be introduced and its main properties will be emphasized. The applications of the fluorescence and lasing effect of the neutral nitrogen molecules will be introduced, with two examples on spectroscopy and detection of electric field. Finally, we discuss the quenching effect of the lasing effect in atmosphere and the mechanisms responsible will be analyzed. An outlook for the achievement of backward lasing in air will be briefly presented.
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Affiliation(s)
- Haicheng Mei
- Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China.
| | - Hongbing Jiang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Aurélien Houard
- Laboratoire d'Optique Appliquée, ENSTA Paris, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, 828 Boulevard des Maréchaux, Palaiseau Cedex 91762, France
| | - Vladimir Tikhonchuk
- Centre Lasers Intenses et Applications, University of Bordeaux-CNRS-CEA, Talence Cedex 33405, France
- Extreme Light Infrastructure ERIC, ELI Beamlines Facility, Dolní Břežany 25241, Czech Republic
| | - Eduardo Oliva
- Departamento de Ingeniería Energética, ETSI Industriales, Universidad Politécnica de Madrid, Madrid 28006, Spain
- Instituto de Fusión Nuclear "Guillermo Velarde", Universidad Politécnica de Madrid, Madrid 28006, Spain
| | - André Mysyrowicz
- Laboratoire d'Optique Appliquée, ENSTA Paris, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, 828 Boulevard des Maréchaux, Palaiseau Cedex 91762, France
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Chengyin Wu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yi Liu
- Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China.
- CAS Center for Excellence in Ultra-intense Laser Science, Shanghai 201800, China
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Peña J, Reyes D, Richardson M. Filamentation in low pressure conditions. Sci Rep 2022; 12:21365. [PMID: 36494395 PMCID: PMC9734164 DOI: 10.1038/s41598-022-19765-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 09/05/2022] [Indexed: 12/13/2022] Open
Abstract
Filamentation is favorable for many long-range outdoor laser applications, some of which require propagation to or at high altitudes. Understanding how the filamentation process and filament properties are impacted by the low pressure conditions present at high altitudes is essential in designing effective applications. The scaling of filament preconditions with pressure is considered. An increase in critical power and decrease in transition numerical aperture (NA) is predicted to occur with a drop in pressure, indicating that nonlinear pulse propagation and filamentation at high altitudes requires higher energy and a longer assisted focal length than sea level filamentation. A summary of pressure-scaled filament properties is also presented. New simulations demonstrate filamentation at pressures as low as 0.0035 atm (38.5 km altitude) is possible.
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Affiliation(s)
- Jessica Peña
- grid.170430.10000 0001 2159 2859Laser Plasma Laboratory, Townes Laser Institute, College of Optics and Photonics, Center for Directed Energy, University of Central Florida, Orlando, FL 32816 USA
| | - Danielle Reyes
- grid.170430.10000 0001 2159 2859Laser Plasma Laboratory, Townes Laser Institute, College of Optics and Photonics, Center for Directed Energy, University of Central Florida, Orlando, FL 32816 USA ,grid.170430.10000 0001 2159 2859Physics Department, University of Central Florida, Orlando, FL 32816 USA
| | - Martin Richardson
- grid.170430.10000 0001 2159 2859Laser Plasma Laboratory, Townes Laser Institute, College of Optics and Photonics, Center for Directed Energy, University of Central Florida, Orlando, FL 32816 USA ,grid.170430.10000 0001 2159 2859Physics Department, University of Central Florida, Orlando, FL 32816 USA
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Konstantakis P, Dufour PE, Manousidaki M, Koulouklidis AD, Tzortzakis S. Taming femtosecond laser filamentation and supercontinuum generation in liquids using neural networks. OPTICS LETTERS 2022; 47:5445-5448. [PMID: 37219240 DOI: 10.1364/ol.466287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 09/24/2022] [Indexed: 05/24/2023]
Abstract
We report the spectral shaping of supercontinuum generation in liquids by employing properly engineered Bessel beams coupled with artificial neural networks. We demonstrate that given a custom spectrum, neural networks are capable of outputting the experimental parameters needed to generate it experimentally.
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