Transitions Driven by a Missing Frequency

Gürtler, A.; Zande, Wim J. van der

doi:10.1103/physrevlett.93.153002

Cited by 8 publications

(3 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By removing the resonant frequencies, the excited state population is only created transiently during the laser pulse and the angular momentum vanishes after 1 ps due to the depopulation of the excited state. In strong fields, where saturation is reached, an absence of resonant photons may still give an asymptotic population as has been shown before [23]. We observe that the angular momentum now fully correlates with the helicity of the pulse [see Fig.…”

Section: Resultssupporting

confidence: 73%

Ultrafast coherent control of angular momentum during a one-photon excitation

et al. 2011

View full text Add to dashboard Cite

The subpicosecond dynamics of angular momentum transfer in the excited rubidium 5p state is studied in real time by observing photoelectron angular distributions with velocity map imaging. Retrieving the populations of the degenerate Zeeman levels and reconstructing the angular momentum, we show that in the case of resonant excitation the angular momentum does not follow the momentary helicity of the electric field of the pulse. This is in contrast with off-resonant excitation where the angular momentum and pulse helicity are fully correlated. Our study shows how to generate and shape ultrashort pulses of orbital and spin angular momentum in a controllable way.

show abstract

Section: Resultssupporting

confidence: 73%

Ultrafast coherent control of angular momentum during a one-photon excitation

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Through the choice of axis scaling, a Dalitz plot maps the energy sharing of the fragments onto different positions within a circle as shown in figure 5(a), the edge of which is confined by momentum conservation. A detailed explanation of Dalitz plots can be found elsewhere [55,71,73,74]. For the purposes of interpretation, an event that maps to the centre of the circle (denoted by the equilateral triangle) indicates that the three fragments share the final energy equally.…”

Section: Similarity Of Fti and Double Ionization Featuresmentioning

confidence: 99%

Frustrated tunnelling ionization during strong-field fragmentation of D₃⁺

et al. 2012

View full text Add to dashboard Cite

We reveal surprisingly high kinetic energy release in the intense-field fragmentation of D + 3 to D + + D + + D with 10 16 W cm −2 , 790 nm, 40 fs (and 7 fs) laser pulses. This feature strongly mimics the behaviour of the D + + D + + D + channel. From the experimental evidence, we conclude that the origin of the feature is due to frustrated tunnelling ionization, the first observation of this mechanism in a polyatomic system. Furthermore, we unravel evidence of frustrated tunnelling ionization in dissociation, both two-body breakup to D + D + 2 and D + + D 2 , and three-body breakup to D + + D + D. Gesellschaft processes involving either elastic scattering [6][7][8], inelastic scattering [9, 10], or electron-ion recombination [11]. These phenomena have led to the birth of new areas of research such as high-harmonic generation and attosecond science [12][13][14][15], laser-driven electron diffraction imaging [5][6][7][8], molecular orbital tomography [16,17] and electron wavepacket probing of molecular dynamics [18-21]-naming only a few.Related to the electron recollision process, recently Nubbemeyer et al [22] reported a new phenomenon dubbed frustrated tunnelling ionization (FTI). Demonstrated originally in strong-field ionization of helium, Nubbemeyer et al showed that an electron wavepacket that starts to tunnel away from the core in an intense laser field, but fails to acquire sufficient drift momentum to escape the attractive potential of the remaining He + ion, can be captured into an excited Rydberg orbital of the He atom-in effect 'frustrating' the tunnel ionization process. This process must occur during the laser pulse to conserve energy and momentum, most likely during the trailing edge, as the electron is gently decelerated over many laser cycles before being pulled into orbit.The same mechanism has been observed in the dissociative ionization of a few diatomic molecules (H 2 [23], D 2 [24], O 2 [25] and Ar 2 [26][27][28]). For such molecules, following ionization, an electron that is excited to the continuum and driven by the laser field tends to be captured to a Rydberg orbital of one of the two 'Coulomb-exploding' fragment ions. The signature of frustrated tunnelling in molecules is that, counterintuitively, the final kinetic energy release (KER) is similar to that of a Coulomb explosion event even though only one product fragment is charged while the other fragment is neutral [23].This description of FTI uses language, such as electron capture, that is usually reserved for discussions involving ionization. Throughout the paper we use this language for convenience. However, it does pose an interesting question in relation to the actual mechanism for FTI, that is,

show abstract

“…In the case of intense pulses, these transients can generate a significant excited state population [20]. This was employed, for example, by Gürtler and van der Zande [21] in a special case of Rb atoms excited in Rydberg states and terahertz radiation, where the combination of Rabi cycles and post-transients resulted in an enhanced excitation efficiency at specific photon energies, even though, formally, the power spectrum of the resulting pulse lacks the required specific photon energies. In a more practical application, one now implements a scheme using absorption to create a coherent transient to seed LCLS, the x-ray free electron laser in Stanford, using Bragg reflection on a diamond crystal to block a narrow frequency range in the kiloelectron volt photon energy range [22].…”

Section: Introductionmentioning

confidence: 99%

Coherent control of excited state populations in rubidium using Rabi oscillations

Malik¹,

Kimel²,

Zande³

2012

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

View full text Add to dashboard Cite

Complete population inversion is demonstrated analytically in the strong field limit in a three level system using the rubidium 5s-5p-5d transition. We exploit the pre-transients of an amplitude shaped laser pulse to direct the dynamics of the Rabi oscillations such that the population transfer to the excited state can be controlled in a wide range from a strongly enhanced to vanishing one. The excitation is performed under off-resonant conditions. During the intense ultrafast pulse levels shift to such an extent that two-photon resonant excitation becomes possible, even though a frequency spectrum does not contain photons with energies necessary for excitation of an unperturbed system. Within the reach of experimental parameters we demonstrate 70% population transfer.

show abstract

Transitions Driven by a Missing Frequency

Cited by 8 publications

References 20 publications

Ultrafast coherent control of angular momentum during a one-photon excitation

Ultrafast coherent control of angular momentum during a one-photon excitation

Frustrated tunnelling ionization during strong-field fragmentation of D₃⁺

Coherent control of excited state populations in rubidium using Rabi oscillations

Contact Info

Product

Resources

About

Transitions Driven by a Missing Frequency

Cited by 8 publications

References 20 publications

Ultrafast coherent control of angular momentum during a one-photon excitation

Ultrafast coherent control of angular momentum during a one-photon excitation

Frustrated tunnelling ionization during strong-field fragmentation of D3+

Coherent control of excited state populations in rubidium using Rabi oscillations

Contact Info

Product

Resources

About

Frustrated tunnelling ionization during strong-field fragmentation of D₃⁺