Polarization evolution of ultrashort pulses in air

Rostami, Shermineh; Diels, Jean‐Claude; Arissian, Ladan

doi:10.1364/oe.23.003299

Cited by 15 publications

(12 citation statements)

References 17 publications

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“…Furthermore, the orientation of the linearly polarized 428 nm emission follows the major axis of the ellipse of the pump beam. Note that the polarization rotates more than it did for the unfocused beam due to nonlinear polarization rotation [21,31]. We observe identical features for the other available emission lines, but they suffer from too much (471 nm) or too little (391 nm) continuum.…”

supporting

confidence: 57%

“…The colour scale is the normalized transmission of the 800 nm beam through the polarizer. The ellipticity is deduced from the data in each horizontal row using the Jones matrix representation of polarization [31]. The zero point on the vertical and horizontal axes corresponds to the creation and transmission of horizontal polarization, respectively.…”

mentioning

confidence: 99%

“…We use a range of focusing conditions (F-number = 4 to 40) to vary plasma length and formation [33], and a range of pulse widths (25 fs to 200 fs) to vary the significance of the alignment dynamics on N 2 and O 2 in the air [31]. The ellipticity at maximum gain depends on focusing geometry and pulse width but we always observe a strong gain that is enhanced for small ellipticity (0.2 − 0.5) and then falls off with increasing ellipticity.…”

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confidence: 99%

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Testing the Role of Recollision in N2+ Air Lasing

Britton

Laferrière

et al. 2018

Phys. Rev. Lett.

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It has been known for many years that during filamentation of femtosecond light pulses in air, gain is observed on the B to X transition in N_{2}^{+}. While the gain mechanism remains unclear, it has been proposed that recollision, a process that is fundamental to much of strong field science, is critical for establishing gain. We probe this hypothesis by directly comparing the influence of the ellipticity of the pump light on gain in air filaments. Then, we decouple filamentation from gain by measuring the gain in a thin gas jet that we also use for high harmonic generation. The latter allows us to compare the dependence of the gain on the ellipticity of the pump with the dependence of the high harmonic signal on the ellipticity of the fundamental. We find that gain and harmonic generation have very different behavior in both filaments and in the jet. In fact, in a jet we even measure gain with circular polarization. Thus, we establish that recollision does not play a significant role in creating the inversion.

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confidence: 99%

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Testing the Role of Recollision in N2+ Air Lasing

Britton

Laferrière

et al. 2018

Phys. Rev. Lett.

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“…While propagating in air, femtosecond laser filamentation finds a variety of applications, for example, on supercontinuum generation [3,4] , THz radiation [5,6] , conical emission [7] , guiding corona discharges [8] , water condensation and precipitation [9] , air lasing [10,11] , etc. The deposited energy during filamentation is very crucial for the applications [12,13] . For the applications, many parameters of the laser pulse have been used to directly control filaments, such as laser wavelength [14] , pulse energy [7] , chirp and pulse duration [4] , and beam astigmatism and ellipticity [15,16] .…”

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confidence: 99%

Polarization-dependent femtosecond laser filamentation in air

Zhu¹,

Wang²,

Liu³

et al. 2018

Chin. Opt. Lett.

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We report on a systematic study of the laser polarization effect on a femtosecond laser filamentation in air. By changing the laser's ellipticity from linear polarization to circular polarization, the onset position of laser filament formation becomes farther from the focusing optics, the filament length is shorter, and less laser energy is deposited. The laser polarization effect on air filaments is supported by a simulation and analysis of the polarization-dependent critical power and ionization rates in air.

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“…In some of the studies, molecular alignment and delayed birefringence acting on the probe were investigated [43][44][45]. In case of self-induced polarization rotation of the pump, direct measurements [46] using a rotating polarizing cube and indirect measurements [47] using femtosecond laser-induced periodic surface structures (FLIPSS) have observed moderate rotations of the polarization angle pre-and post-collapse. The fluctuations in polarization rotation in these studies, however, were obscured by averaging over multiple shots or pulse periods, and the increase of the fluctuations with propagation distance at powers significantly above P cr was not revealed.…”

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Loss of Polarization in Collapsing Beams of Elliptical Polarization

Patwardhan

Gao

Dutt

et al. 2017

Conference on Lasers and Electro-Optics

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We show theoretically and demonstrate experimentally that collapsing elliptically-polarized laser beams experience a nonlinear ellipse rotation that is highly sensitive to small fluctuations in the input power. For arbitrarily small fluctuations in the input power and after a sufficiently large propagation distance, the polarization angle becomes uniformly distributed in [0, 2π] from shot-toshot. We term this novel phenomenon loss of polarization. We perform experiments in fused-silica glass, nitrogen gas and water, and observe a significant increase in the fluctuations of the output polarization angle for elliptically-polarized femtosecond pulses as the power is increased beyond the critical power for self-focusing. We also show numerically and confirm experimentally that this effect is more prominent in the anomalous group-velocity dispersion (GVD) regime compared to the normal-GVD regime due to the extended lengths of the filaments for the former. Such effects could play an important role in intense-field light-matter interactions in which elliptically-polarized pulses are utilized. arXiv:1808.07019v1 [physics.optics]

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Polarization evolution of ultrashort pulses in air

Cited by 15 publications

References 17 publications

Testing the Role of Recollision in N2+ Air Lasing

Testing the Role of Recollision in N2+ Air Lasing

Polarization-dependent femtosecond laser filamentation in air

Loss of Polarization in Collapsing Beams of Elliptical Polarization

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