Population dynamics of molecular nitrogen initiated by intense femtosecond laser pulses

Wang, Peng; Wu, Chengyin; Lei, Mingwei; Dai, Bo; Yang, Hong; Jiang, Hongbing; Gong, Qihuang

doi:10.1103/physreva.92.063412

Cited by 21 publications

(12 citation statements)

References 28 publications

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“…More interestingly, at low gas pressures in the range from 10 to 30 mbar, pronounced supercontinuum spectra with a bandwidth of ∼80 nm have been observed which fill up the gap between ∼331 and ∼358 nm as well as that between ∼358 and ∼391 nm. In previous reports [5,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], + N 2 coherent emissions from different vibrational transitions between ground and excited states show an extremely narrow spectral bandwidth. To our knowledge, this is the first observation of coherent supercontinuum generated in + N 2 ions at low gas pressures.…”

Section: Resultsmentioning

confidence: 86%

“…With the tunnel ionization as the initiative process, highly nonlinear processes such as high-order harmonic generation [2], above threshold ionization [3], and non-sequential double ionization [4] have been observed, which further provide the means to access the dynamics in atomic and molecular systems on attosecond time scale. Recently, lasing actions induced by tunnel ionization of nitrogen molecules have been observed which come as a major surprise to those who have been investigating strong field physics over the past three decades [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. These observations were made with either a pump laser at 800 nm wavelength [6,[8][9][10][11][12][13][14][15][16][17][18][19][20][21] or that at longer wavelengths in the range between 1 and 4 μm [5,7,23].…”

Section: Introductionmentioning

confidence: 99%

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Generation of Raman lasers from nitrogen molecular ions driven by ultraintense laser fields

et al. 2018

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Atmospheric lasing has aroused much interest in the past few years. The 'air-laser' opens promising potential for remote chemical sensing of trace gases with high sensitivity and specificity. At present, several approaches have been successfully implemented for generating highly coherent laser beams in atmospheric condition, including both amplified-spontaneous emission, and narrow-bandwidth stimulated emission in the forward direction in the presence of self-generated or externally injected seed pulses. Here, we report on generation of multiple-wavelength Raman lasers from nitrogen molecular ions ( + N 2 ), driven by intense mid-infrared laser fields. Intuitively, the approach appears problematic for the small nonlinear susceptibility of + N 2 ions, whereas the efficiency of Raman laser can be significantly promoted in near-resonant condition. More surprisingly, a Raman laser consisting of a supercontinuum spanning from ∼310 to ∼392 nm has been observed resulting from a series nearresonant nonlinear processes including four-wave mixing, stimulated Raman scattering and cross phase modulation. To date, extreme nonlinear optics in molecular ions remains largely unexplored, which provides an alternative means for air-laser-based remote sensing applications.

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Section: Resultsmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Generation of Raman lasers from nitrogen molecular ions driven by ultraintense laser fields

et al. 2018

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“…Molecular nitrogen ion (N

_{2}^{+}

) lasing is the third type of air lasing, which originates from the transition from the excited state

B^{2} {normalΣ}_{u}^{+}

to the ground state

X^{2} {normalΣ}_{g}^{+}

. Lasing actions from N

_{2}^{+}

ions have been experimentally observed by several research groups since the first report in 2011 . Besides its promising application in the remote sensing similar to the other two types of air lasing, the understanding of the physical procedure in N

_{2}^{+}

lasing is also attracting great interests.…”

Section: Molecular Nitrogen Ion Lasingmentioning

confidence: 99%

Recent Advances in Air Lasing: A Perspective from Quantum Coherence

et al. 2019

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The research topic of air lasing is of fundamental and practical importance, which has grown rapidly in the past decade. Air lasing, or a laser‐like emission from air species including atomic oxygen, atomic argon, atomic nitrogen, molecular nitrogen, and molecular nitrogen ions, has been investigated vastly in both experiment and theory. In this review, the basic concepts of air lasing are discussed and the crucial role of quantum coherence in the air‐lasing process is highlighted. As an exciting perspective, air lasing not only exhibits important fundamental physics such as superradiance, nonlinear effects, vibrational and rotational dynamics, but also shows potential practical implications toward remote sensing.

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“…Recently, it is observed that the non-perturbative interaction of intense laser fields with molecules can enable to generate laser-like narrow-bandwidth coherent emissions instantly after the photoionization [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The wavelength of each narrow-bandwidth emission is in accordance with one of transitions between the vibrational energy levels of excited  state [4].…”

mentioning

confidence: 99%

“…The wavelength of each narrow-bandwidth emission is in accordance with one of transitions between the vibrational energy levels of excited  state [4]. To understand the intriguing phenomenon, pump-probe measurements have been earlier carried out by setting the pump wavelength at ~800 nm and the probe wavelength around 391 nm, corresponding to the transition between   [7,8,[10][11][12][13][14]16,17]. The time window of gain, which covers multiple revival periods of rotational wavepackets in 2 N  ions, provides clear evidence on the population inversion between excited and ground states.…”

mentioning

confidence: 99%

Near-Resonant Raman Amplification in the Rotational Quantum Wave Packets of Nitrogen Molecular Ions Generated by Strong Field Ionization

et al. 2018

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The generation of laserlike narrow bandwidth emissions from nitrogen molecular ions (N_{2}^{+}) generated in intense near- and mid infrared femtosecond laser fields has aroused much interest because of the mysterious physics underlying such a phenomenon. Here, we perform a pump-probe measurement on the nonlinear interaction of rotational quantum wave packets of N_{2}^{+} generated in midinfrared (e.g., at a wavelength centered at 1580 nm) femtosecond laser fields with an ultrashort probe pulse whose broad spectrum overlaps both P- and R-branch rotational transition lines between the electronic states N_{2}^{+}(B^{2}Σ_{u}^{+},v^{'}=0) and N_{2}^{+}(X^{2}Σ_{g}^{+},v=0). The results indicate the occurrence of highly efficient near-resonant stimulated Raman scattering in the quantum wave packets of N_{2}^{+} ions generated in strong laser fields in the midinfrared region, of which the underlying mechanism is different from that of the air lasers generated in atmospheric environment when pumping with 800 nm intense pulses.

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Population dynamics of molecular nitrogen initiated by intense femtosecond laser pulses

Cited by 21 publications

References 28 publications

Generation of Raman lasers from nitrogen molecular ions driven by ultraintense laser fields

Generation of Raman lasers from nitrogen molecular ions driven by ultraintense laser fields

Recent Advances in Air Lasing: A Perspective from Quantum Coherence

Near-Resonant Raman Amplification in the Rotational Quantum Wave Packets of Nitrogen Molecular Ions Generated by Strong Field Ionization

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