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Iordanova E, Yankov G, Karatodorov S, Kovachev L. Exceeding the Boundaries of the Paraxial Spatiotemporal Nonlinear Optics and Filamentation for Ultrashort Laser Pulses. ACS OMEGA 2023; 8:3501-3508. [PMID: 36713697 PMCID: PMC9878667 DOI: 10.1021/acsomega.2c07703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 12/28/2022] [Indexed: 06/18/2023]
Abstract
An impressive phenomenon of observed plasma instability and conical emission under the propagation of ultrashort laser pulses in the air is reported. The discussed novel findings demonstrating nonlinear effects are incapable to be explained in the standard spatiotemporal paraxial optics. Three main mechanisms are investigated. The first one is related to the nonlinear nonparaxial mechanisms for waveguiding of femtosecond pulses, and the second one considers the mechanism of single filament formation at weak ionization. The third mechanism demonstrates a new physical effect leading to collision ionization with intensities in the range of 1010-1011 W/cm2. Furthermore, a new ionization regime of instability is suggested at intensities below the critical thresholds for multiphoton and tunnel ionization. The experimental results and findings are supported by theoretical analyses and numerical simulations.
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Affiliation(s)
- Ekaterina Iordanova
- Institute
of Solid State Physics, Bulgarian Academy
of Sciences, 72 Tsarigradsko
Chaussee blvd., Sofia1784, Bulgaria
| | - Georgi Yankov
- Institute
of Solid State Physics, Bulgarian Academy
of Sciences, 72 Tsarigradsko
Chaussee blvd., Sofia1784, Bulgaria
| | - Stefan Karatodorov
- Institute
of Solid State Physics, Bulgarian Academy
of Sciences, 72 Tsarigradsko
Chaussee blvd., Sofia1784, Bulgaria
| | - Lubomir Kovachev
- Institute
of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee blvd., Sofia1784, Bulgaria
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2
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Morales F, Richter M, Ivanov M, Husakou A. Non-instantaneous third-order optical response of gases in low-frequency fields. OPTICS EXPRESS 2022; 30:23579-23586. [PMID: 36225034 DOI: 10.1364/oe.458765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/13/2022] [Indexed: 06/16/2023]
Abstract
It is commonly assumed that for low-intensity short optical pulses far from resonance, the third-order optical nonlinear response is instantaneous. We solve the three-dimensional time-dependent Schrödinger equation for the hydrogen atom and show that this is not the case: the polarization is not simply proportional to the cube of the electric field even at low intensities. We analyze the fundamental-frequency and third-harmonic nonlinear susceptibilities of hydrogen, investigate their dependence on intensity, and find that the delays in the Kerr response rapidly approach the femtosecond time-scale at higher intensities, while the delays in the third harmonic generation remain much lower. We also propose an experimental scheme to detect and characterize the above effects.
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3
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Nesrallah M, Hakami A, Bart G, McDonald CR, Varin C, Brabec T. Measuring the Kerr nonlinearity via seeded Kerr instability amplification: conceptual analysis. OPTICS EXPRESS 2018; 26:7646-7654. [PMID: 29609317 DOI: 10.1364/oe.26.007646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Whereas the Kerr nonlinearity is well understood in the perturbative limit of nonlinear optics, there is considerable discussion about its functional form and magnitude at extreme intensities, at which point matter starts to ionize. Here, we introduce a concept to answer this question and theoretically analyze its feasibility. We demonstrate that seeded Kerr instability amplification provides clear signatures from which functional form and magnitude of the Kerr nonlinearity can be extracted in the non-perturbative limit of nonlinear optics.
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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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5
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Abstract
Femtosecond laser filamentation occurs as a dynamic balance between the self-focusing and plasma defocusing of a laser pulse to produce ultrashort radiation as brief as a few optical cycles. This unique source has many properties that make it attractive as a nonlinear optical tool for spectroscopy, such as propagation at high intensities over extended distances, self-shortening, white-light generation, and the formation of an underdense plasma. The plasma channel that constitutes a single filament and whose position in space can be controlled by its input parameters can span meters-long distances, whereas multifilamentation of a laser beam can be sustained up to hundreds of meters in the atmosphere. In this review, we briefly summarize the current understanding and use of laser filaments for spectroscopic investigations of molecules. A theoretical framework of filamentation is presented, along with recent experimental evidence supporting the established understanding of filamentation. Investigations carried out on vibrational and rotational spectroscopy, filament-induced breakdown, fluorescence spectroscopy, and backward lasing are discussed.
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Affiliation(s)
- Johanan Odhner
- Department of Chemistry and Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122
| | - Robert Levis
- Department of Chemistry and Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122
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Huang TW, Zhou CT, He XT. Pattern dynamics and filamentation of femtosecond terawatt laser pulses in air including the higher-order Kerr effects. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:053103. [PMID: 23767639 DOI: 10.1103/physreve.87.053103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Indexed: 06/02/2023]
Abstract
Plasma defocusing and higher-order Kerr effects on multiple filamentation and pattern formation of ultrashort laser pulse propagation in air are investigated. Linear analyses and numerical results show that these two saturable nonlinear effects can destroy the coherent evolution of the laser field, and small-scale spatial turbulent structures rapidly appear. For the two-dimensional case, numerical simulations show that blow-up-like solutions, spatial chaos, and pseudorecurrence can appear at higher laser intensities if only plasma defocusing is included. These complex patterns result from the stochastic evolution of the higher- or shorter-wavelength modes of the laser light spectrum. From the viewpoint of nonlinear dynamics, filamentation can be attributed to the modulational instability of these spatial incoherent localized structures. Furthermore, filament patterns associated with multiphoton ionization of the air molecules with and without higher-order Kerr effects are compared.
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Affiliation(s)
- T W Huang
- HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100871, People's Republic of China
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Gao H, Chu W, Yu G, Zeng B, Zhao J, Wang Z, Liu W, Cheng Y, Xu Z. Femtosecond laser filament array generated with step phase plate in air. OPTICS EXPRESS 2013; 21:4612-4622. [PMID: 23481994 DOI: 10.1364/oe.21.004612] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Femtosecond laser filament arrays are generated in air by using three kinds of step phase plates with π phase lag, namely, the semicircular phase plate (SCPP), the quarter-circle phase plate (QCPP) and eight-octant phase plate (EOPP). Experimental results and simulations show that filament arrays consisting of two, four and eight filaments, respectively, are produced by three phase plates. The transverse patterns of the filament arrays are determined by the geometrical shapes of the phase plates. At the same time, the separation distances are found to vary with the focal lengths of the used lenses. We further propose that by using an axicon, filament array in the form of ring shape could be realized while the lengths of the filaments could be significantly elongated at the same time. Our study has suggested a realistic method to generate filament array by the step phase plate with π phase lag.
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Affiliation(s)
- Hui Gao
- Institute of Modern Optics, Nankai University, Key Laboratory of Optical Information Science and Technology, Ministry of Education, Tianjin 300071, China
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Bache M, Eilenberger F, Minardi S. Higher-order Kerr effect and harmonic cascading in gases. OPTICS LETTERS 2012; 37:4612-4614. [PMID: 23164855 DOI: 10.1364/ol.37.004612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The higher-order Kerr effect (HOKE) has recently been advocated to explain measurements of the saturation of the nonlinear refractive index in gases. Here we show that cascaded third-harmonic generation results in an effective fifth-order nonlinearity that is negative and significant. Higher-order harmonic cascading will also occur from the HOKE, and the cascading contributions may significantly modify the observed nonlinear index change. At lower wavelengths, cascading increases the HOKE saturation intensity, while for longer wavelengths cascading will decrease the HOKE saturation intensity.
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Affiliation(s)
- Morten Bache
- DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Lyngby DK-2800 Kgs, Denmark.
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