Propagation effects in high-order harmonic generation in rare gases

L’Huillier, Anne; Li, X. F.; Lompré, L. A.

doi:10.1364/josab.7.000527

Cited by 103 publications

(34 citation statements)

References 53 publications

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“…The dynamic polarizability α pol (ω) is positive at 800 nm, equal to about 1.6 × 10 −24 cm 3 for argon and 0.4 × 10 −24 cm 3 for neon [21]. Since the photon energy for the harmonics considered in the present work is above the ionization limit, α pol (qω) is negative but of the same order of magnitude as α pol (ω) [22]. We estimate the number of neutral atoms in the following way.…”

Section: Dispersion Due To Neutral Atomsmentioning

confidence: 68%

Influence of the medium length on high-order harmonic generation

Delfin¹,

Altucci

Fabbri

et al. 1999

J. Phys. B: At. Mol. Opt. Phys.

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Influence of the medium length on high-order harmonic generationDelfin, C; Altucci, C; De Filippo, F; de Lisio, C; Gaarde, Mette; Lhuillier, A; Roos, L; Wahlström, Claes-Göran Link to publication Citation for published version (APA): Delfin, C., Altucci, C., De Filippo, F., de Lisio, C., Gaarde, M., L'Huillier, A., ... Wahlström, C-G. (1999). Influence of the medium length on high-order harmonic generation. Journal of Physics B: Atomic, Molecular and Optical Physics, 32(22), 5397-5409. DOI: 10.1088/0953-4075/32/22/316 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Influence of the medium length on high-order harmonic generation Influence of the medium length on high-order harmonic generation Abstract. We study high-order harmonic generation using a 110 fs Ti:sapphire laser loosely focused into a variable-length gas cell filled with neon or argon at 5 mbar pressure. The harmonic intensity is recorded as a function of the medium length, varying between 2 and 21 mm. Several cases are examined, the 17th and the 29th harmonic in argon, and the 29th and 51st harmonic in neon, at the same intensity 4 × 10 14 W cm −2 . We find that the length which maximizes the harmonic yield varies from 10 mm to more than 20 mm. We discuss the different effects affecting the photon yield of the high-order harmonics.

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Section: Dispersion Due To Neutral Atomsmentioning

confidence: 68%

Influence of the medium length on high-order harmonic generation

Delfin¹,

Altucci

Fabbri

et al. 1999

J. Phys. B: At. Mol. Opt. Phys.

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“…The presence of free electrons that are due to ionization of the medium introduces a substantial phase mismatch between the generated field and the driving nonlinear polarization. The atomic phase mismatch is in general negligible compared with that induced by the free electrons, 29 especially for high-order harmonics, because the latter contribution, 2qdk 1 , is proportional to the harmonic order q. Moreover, these electrons can give rise to significant defocusing 14,26 as well as spectral blue shifting 9,16 of the fundamental field.…”

Section: Interpretation Of the Experimental Resultsmentioning

confidence: 99%

Influence of atomic density in high-order harmonic generation

et al. 1996

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Influence of atomic density in high-order harmonic generationAltucci, C; Starczewski, Tomas; Mevel, E; Wahlström, Claes-Göran; Carre, B; Lhuillier, A Link to publication Citation for published version (APA): Altucci, C., Starczewski, T., Mevel, E., Wahlström, C-G., Carre, B., & L'Huillier, A. (1996). Influence of atomic density in high-order harmonic generation. Optical Society of America. Journal B: Optical Physics, 13(1), 148-156. DOI: 10.1364/JOSAB.13.000148General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. We have investigated how high-order harmonics generated in rare gases depend on the atomic density. The peak and the profile of the atomic density in the interaction region were measured as a function of the backing pressure and the distance from the nozzle by a differential interferometry technique. The conversion efficiency for the harmonics in the plateau was found to increase approximately quadratically over the entire range of peak pressures investigated (3 -80 mbar). The intensity of the harmonics in the cutoff region, in contrast, increased only until an optimum peak pressure was reached, beyond which it decreased. This optimum peak pressure was found to be dependent on both the laser intensity and the process order. To understand this effect, we have performed extensive propagation calculations of both the fundamental and the harmonic fields, using ionization rates and dipole moments from a tunnel ionization model. We obtained good agreement with the experimental results. The observed effect is attributed to ionization-induced defocusing of the fundamental laser beam, which reduces the peak intensity obtained in the medium and shortens the extent of the plateau.

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“…If we use theoretical ab initio values for the dynamic polarizabilities in the weak-field limit from Ref. 10, an estimate of, e.g., Ak 7 , with a density corresponding to the experimental condition (p = 15 Torr) and a laser wavelength of 1.053 ,um, gives Ak 7 = 3.3 cm-' in neutral xenon and, for a free-electron gas with the same number density, Ak 7 = 110 cm'1. Clearly the phase mismatch due to the free electrons completely dominates the mismatch due to the dispersion in the neutral gas.…”

Section: Numerical Modelmentioning

confidence: 99%

Studies of time-resolved harmonic generation in intense laser fields in xenon

et al. 1992

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We report preliminary experimental and computational studies of the temporal evolution of the harmonics, generated in xenon, by 50-ps pulses from a Nd: YLF laser, amplified in Nd: glass amplifiers, and focused to produce intensities in the range 1013-5 X 1013 W cm 2 . Measurements were made of the temporal profiles of the seventh-and ninth-order harmonics using a specially modified VUV streak camera with better than 7-ps temporal resolution. These results were compared with predictions of a numerical model that included the effects of neutral atom depletion and photoelectron dispersion in the calculation of the harmonic output as a function of time.

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Propagation effects in high-order harmonic generation in rare gases

Cited by 103 publications

References 53 publications

Influence of the medium length on high-order harmonic generation

Influence of the medium length on high-order harmonic generation

Influence of atomic density in high-order harmonic generation

Studies of time-resolved harmonic generation in intense laser fields in xenon

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