Theory of femtosecond strong field ion excitation and subsequent lasing in
Delayed cavity-free forward lasing at the wavelengths of 391 and 428 nm was observed in recent experiments in air or pure nitrogen pumped with an intense femtosecond laser pulse at wavelength of 800 nm. The mechanism responsible for the lasing is highly controversial. In this article we propose a mo...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2021-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/abd8bf |
| _version_ | 1797750258921373696 |
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| author | V T Tikhonchuk Y Liu R Danylo A Houard A Mysyrowicz |
| author_facet | V T Tikhonchuk Y Liu R Danylo A Houard A Mysyrowicz |
| author_sort | V T Tikhonchuk |
| collection | DOAJ |
| description | Delayed cavity-free forward lasing at the wavelengths of 391 and 428 nm was observed in recent experiments in air or pure nitrogen pumped with an intense femtosecond laser pulse at wavelength of 800 nm. The mechanism responsible for the lasing is highly controversial. In this article we propose a model explaining the delayed lasing, which contains two parts: (i) ionization of neutral nitrogen molecules and subsequent excitation of nitrogen ions in a strong pump laser pulse, and (ii) coherent emission of excited ions due to the presence of long-lived polarizations maintained by a weak laser post-pulse and coupling simultaneously ground state ${\mathrm{X}}^{2}{{\Sigma}}_{\mathrm{g}}^{+}$ to states A ^2 Π _u and ${\mathrm{B}}^{2}{{\Sigma}}_{u}^{+}$ of singly ionized nitrogen molecules ${\mathrm{N}}_{2}^{+}$ . Two regimes of signal amplification are identified: a signal of a few picosecond duration at low gas pressures and a short (sub-picosecond) signal at high gas pressures. The theoretical model compares favorably with results obtained by different experimental groups. |
| first_indexed | 2024-03-12T16:30:05Z |
| format | Article |
| id | doaj.art-07962ceeb0bf426fb681e1cba9558cbf |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:30:05Z |
| publishDate | 2021-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-07962ceeb0bf426fb681e1cba9558cbf2023-08-08T15:30:53ZengIOP PublishingNew Journal of Physics1367-26302021-01-0123202303510.1088/1367-2630/abd8bfTheory of femtosecond strong field ion excitation and subsequent lasing inV T Tikhonchuk0https://orcid.org/0000-0001-7532-5879Y Liu1https://orcid.org/0000-0002-0821-7322R Danylo2https://orcid.org/0000-0003-0112-1659A Houard3https://orcid.org/0000-0002-2072-6680A Mysyrowicz4https://orcid.org/0000-0001-8129-1783University of Bordeaux-CNRS-CEA , CELIA, UMR 5107, 33405 Talence, France; ELI-Beamlines, Institute of Physics , Czech Academy of Sciences, 25241 Dolní Břežany, Czech RepublicShanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology , 200093 Shanghai, People’s Republic of China; CAS Center for Excellence in Ultra-intense Laser Science, Shanghai, 201800, People’s Republic of ChinaShanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology , 200093 Shanghai, People’s Republic of China; Laboratoire d’Optique Appliquée, ENSTA Paris, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris , 91762 Palaiseau, FranceLaboratoire d’Optique Appliquée, ENSTA Paris, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris , 91762 Palaiseau, FranceLaboratoire d’Optique Appliquée, ENSTA Paris, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris , 91762 Palaiseau, FranceDelayed cavity-free forward lasing at the wavelengths of 391 and 428 nm was observed in recent experiments in air or pure nitrogen pumped with an intense femtosecond laser pulse at wavelength of 800 nm. The mechanism responsible for the lasing is highly controversial. In this article we propose a model explaining the delayed lasing, which contains two parts: (i) ionization of neutral nitrogen molecules and subsequent excitation of nitrogen ions in a strong pump laser pulse, and (ii) coherent emission of excited ions due to the presence of long-lived polarizations maintained by a weak laser post-pulse and coupling simultaneously ground state ${\mathrm{X}}^{2}{{\Sigma}}_{\mathrm{g}}^{+}$ to states A ^2 Π _u and ${\mathrm{B}}^{2}{{\Sigma}}_{u}^{+}$ of singly ionized nitrogen molecules ${\mathrm{N}}_{2}^{+}$ . Two regimes of signal amplification are identified: a signal of a few picosecond duration at low gas pressures and a short (sub-picosecond) signal at high gas pressures. The theoretical model compares favorably with results obtained by different experimental groups.https://doi.org/10.1088/1367-2630/abd8bfmolecular excitation and ionizationpopulation inversionoptical parametric amplification |
| spellingShingle | V T Tikhonchuk Y Liu R Danylo A Houard A Mysyrowicz Theory of femtosecond strong field ion excitation and subsequent lasing in New Journal of Physics molecular excitation and ionization population inversion optical parametric amplification |
| title | Theory of femtosecond strong field ion excitation and subsequent lasing in |
| title_full | Theory of femtosecond strong field ion excitation and subsequent lasing in |
| title_fullStr | Theory of femtosecond strong field ion excitation and subsequent lasing in |
| title_full_unstemmed | Theory of femtosecond strong field ion excitation and subsequent lasing in |
| title_short | Theory of femtosecond strong field ion excitation and subsequent lasing in |
| title_sort | theory of femtosecond strong field ion excitation and subsequent lasing in |
| topic | molecular excitation and ionization population inversion optical parametric amplification |
| url | https://doi.org/10.1088/1367-2630/abd8bf |
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