Attosecond Temporal Gating with Elliptically Polarized Light

Dudovich, Nirit; Lévesque, Julie; Smirnova, Olga; Zeidler, D.; Comtois, D.; Ivanov, Misha; Villeneuve, D. M.; Corkum, P. B.

doi:10.1103/physrevlett.97.253903

Cited by 43 publications

(30 citation statements)

References 24 publications

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“…r þ . The HHG efficiency is maximized for vanishing v y0 [24,25]. If the bound state has spherical symmetry, the amplitude ratio R is fully determined by the return velocity vector, namely, R ¼ jv y ð r Þ=v x ð r Þj.…”

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confidence: 99%

Determination of Ionization and Tunneling Times in High-Order Harmonic Generation

Zhao

Lein

2013

Phys. Rev. Lett.

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From the numerical solution of the time-dependent Schrödinger equation, we obtain the times of ionization and return of the laser-driven electron in high-order harmonic generation by probing the dynamics with a second harmonic field polarized orthogonal to the fundamental field and observing the harmonic emission in dependence on the two-color delay. Our retrieval method using complex-time evolution gives ionization and return times in excellent agreement with the quantum-orbit model, while a retrieval based on real-time classical dynamics can introduce substantial errors. Because of the imaginary parts, the harmonic signal polarized along the probe field is nonzero for any two-color delay. The tunneling time can be retrieved under an assumption for the return time. DOI: 10.1103/PhysRevLett.111.043901 PACS numbers: 42.65.Ky, 32.80.Rm High-order harmonic generation (HHG) from atoms or molecules exposed to strong laser pulses has been intensively investigated in the past two decades [1,2]. HHG as a highly nonlinear process provides a unique source of coherent extreme ultraviolet radiation in the form of single attosecond pulses or attosecond pulse trains, which paves the way for monitoring and controlling electronic dynamics on the attosecond time scale [3,4]. Because the HHG signal contains information about electronic dynamics and molecular structure, it is also extensively used for highharmonic spectroscopy [5][6][7][8][9][10].The key to understanding HHG is the three-step model [2]: An electron tunnels into the continuum through the potential barrier formed by the atomic potential and the laser field. Then the electron is accelerated as a free particle in the strong oscillating field. Finally, the electron may recollide with the parent ion and recombine to the initial state by emission of an extreme ultraviolet photon. The photon carries away the sum of the binding energy and the electronic kinetic energy acquired in the continuum. Classical electron dynamics in the continuum is sufficient to explain approximately the cutoff in the harmonic spectrum, but the initial tunnel ionization is a quantummechanical process that requires separate treatment. A complete quantum-mechanical description, based on the strong-field approximation, was developed to give a quantitative treatment of HHG [1]. Resulting from this approach is the quantum-orbit (QO) model, where each harmonic emission frequency is attributed to a few dominant quantum trajectories evolving in complex time [11]. The question arises how accurately reality follows these model trajectories, especially since time-resolved highharmonic spectroscopy is based on the knowledge of the electron excursion times. Another question concerns the physical meaning of the imaginary parts.With the development of time-resolved methods operating on the attosecond scale, the precise timing of electron release from an atom has been investigated for various types of ionization processes. As for single-photon ionization, isolated attosecond pulses were applied to set electr...

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confidence: 99%

Determination of Ionization and Tunneling Times in High-Order Harmonic Generation

Zhao

Lein

2013

Phys. Rev. Lett.

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“…Only those with a certain initial lateral velocity, which may compensate the displacement induced by the lateral electric field, can return to the core and contribute to the NSDI yield. The effect of the transverse velocity has been demonstrated in HHG by a recent experiment where an elliptical laser pulse was employed [20].…”

Section: Resultsmentioning

confidence: 99%

“…If both effects are combined, a gate can be formed to choose the orbit with a certain initial lateral velocity to come back with highest probability [20]. A larger lateral velocity corresponds to a stronger lateral laser electric field and, according to Eq.…”

Section: Pulsesmentioning

confidence: 99%

Nonsequential double ionization with polarization-gated pulses

Quan¹,

Liu²,

Faria³

2009

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

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Abstract. We investigate laser-induced nonsequential double ionization by a polarization-gated laser pulse, constructed employing two counter-rotating circularly polarized few cycle pulses with a time delay T d . We address the problem within a classical framework, and mimic the behavior of the quantum-mechanical electronic wave packet by means of an ensemble of classical electron trajectories. These trajectories are initially weighted with the quasi-static tunneling rate, and with suitably chosen distributions for the momentum components parallel and perpendicular to the laser-field polarization, in the temporal region for which it is nearly linearly polarized. We show that, if the time delay T d is of the order of the pulse length, the electron-momentum distributions, as functions of the parallel momentum components, are highly asymmetric and dependent on the carrier-envelope (CE) phase. As this delay is decreased, this asymmetry gradually vanishes. We explain this behavior in terms of the available phase space, the quasistatic tunneling rate and the recollision rate for the first electron, for different sets of trajectories. Our results show that polarization-gating technique may provide an efficient way to study the NSDI dynamics in the single-cycle limit, without employing few-cycle pulses.

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“…High-order harmonic generation (HHG) is a method to generate coherent sources of extreme ultraviolet (XUV) radiation, which has opened new frontiers in science by pushing ultrafast science to the attosecond domain [1]. Progress in attosecond science has revealed many new phenomena that have never been seen with femtosecond pulses.…”

Section: Introductionmentioning

confidence: 99%

Improved efficiency and divergence of intense high-order harmonics from carbon plasma

Pertot

Fouquet

Ozaki

2012

IEEE Photonics Conference 2012

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We improve the efficiency and divergence of high-order harmonics from carbon plasma, which could be pumped with sub-mJ laser. This opens the possibility for high repetition rate experiments with intense attosecond pulses. IntroductionHigh-order harmonic generation (HHG) is a method to generate coherent sources of extreme ultraviolet (XUV) radiation, which has opened new frontiers in science by pushing ultrafast science to the attosecond domain [1]. Progress in attosecond science has revealed many new phenomena that have never been seen with femtosecond pulses. Clearly, the next frontier is to study nonlinear effects at the attosecond timescale and in the XUV. However, a problem with present-day attosecond pulses is that they are just too weak to induce measurable nonlinearities, which severely limits the application of this source. Since attosecond experiments require data accumulation, kHz repetition rate, isolated attosecond pulses with µJ energy will enable us to enter a completely new phase in attoscience.

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Attosecond Temporal Gating with Elliptically Polarized Light

Cited by 43 publications

References 24 publications

Determination of Ionization and Tunneling Times in High-Order Harmonic Generation

Determination of Ionization and Tunneling Times in High-Order Harmonic Generation

Nonsequential double ionization with polarization-gated pulses

Improved efficiency and divergence of intense high-order harmonics from carbon plasma

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