Strong-field ionization (SFI) is a key process for accessing real-time quantum dynamics of electrons on the attosecond timescale. The theoretical foundation of SFI was pioneered in the 1960s, and later refined by various analytical models. While asymptotic ionization rates predicted by these models have been tested to be in reasonable agreement for a wide range of laser parameters, predictions for SFI on the sub-laser-cycle timescale are either beyond the scope of the models or show strong qualitative deviations from full quantum-mechanical simulations. Here, using the unprecedented state specificity of attosecond transient absorption spectroscopy, we follow the real-time SFI process of the two valence spin–orbit states of xenon. The results reveal that the irreversible tunnelling contribution is accompanied by a reversible electronic population that exhibits an observable spin–orbit-dependent phase delay. A detailed theoretical analysis attributes this observation to transient ground-state polarization, an unexpected facet of SFI that cannot be captured by existing analytical models that focus exclusively on the production of asymptotic electron/ion yields.
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Keldysh, L. V. Ionization in the field of a strong electromagnetic wave. Sov. Phys. JETP 20, 1307–1314 (1965).
Voronov, G. S. & Delone, N. B. Many-photon ionization of the xenon atom by ruby laser radiation. Sov. Phys. JETP 23, 54–58 (1966).
Chin, S. L., Yergeau, F. & Lavigne, P. Tunnel ionisation of Xe in an ultra-intense CO2 laser field (1014 W cm−2) with multiple charge creation. J. Phys. B 18, L213 (1985).
Augst, S., Meyerhofer, D. D., Strickland, D. & Chin, S. L. Laser ionization of noble gases by Coulomb-barrier suppression. J. Opt. Soc. Am. B 8, 858–867 (1991).
Monot, P., Auguste, T., Lompré, L. A., Mainfray, G. & Manus, C. Focusing limits of a terawatt laser in an underdense plasma. J. Opt. Soc. Am. B 9, 1579–1584 (1992).
Drescher, M. et al. Time-resolved atomic inner-shell spectroscopy. Nature 419, 803–807 (2002).
Cavalieri, A. L. et al. Attosecond spectroscopy in condensed matter. Nature 449, 1029–1032 (2007).
Neppl, S. et al. Attosecond time-resolved photoemission from core and valence states in magnesium. Phys. Rev. Lett. 109, 087401 (2012).
Schultze, M. et al. Delay in photoemission. Science 328, 1658–1662 (2010).
Klünder, K. et al. Probing single-photon ionization on the attosecond time scale. Phys. Rev. Lett. 106, 143002 (2011).
Sabbar, M. et al. Resonance effects in photoemission time delays. Phys. Rev. Lett. 115, 133001 (2015).
Uiberacker, M. et al. Attosecond real-time observation of electron tunnelling in atoms. Nature 446, 627–632 (2007).
Goulielmakis, E. et al. Real-time observation of valence electron motion. Nature 466, 739–743 (2010).
Wang, H. et al. Attosecond time-resolved autoionization of argon. Phys. Rev. Lett. 105, 143002 (2010).
Holler, M., Schapper, F., Gallmann, L. & Keller, U. Attosecond electron wave-packet interference observed by transient absorption. Phys. Rev. Lett. 106, 123601 (2011).
Wirth, A. et al. Synthesized light transients. Science 334, 195–200 (2011).
Dalgarno, A. & Kingston, A. E. The refractive indices and Verdet constants of the inert gases. Proc. R. Soc. Lond. A 259, 424–431 (1960).
Langhoff, P. W. & Karplus, M. Padé summation of the Cauchy dispersion equation. J. Opt. Soc. Am. 59, 863–871 (1969).
Smirnova, O., Spanner, M. & Ivanov, M. Coulomb and polarization effects in sub-cycle dynamics of strong-field ionization. J. Phys. B 39, S307 (2006).
Dimitrovski, D. & Madsen, L. B. Time dependence of ionization and excitation by few-cycle laser pulses. Phys. Rev. A 78, 043424 (2008).
Greenman, L. et al. Implementation of the time-dependent configuration-interaction singles method for atomic strong-field processes. Phys. Rev. A 82, 023406 (2010).
Rohringer, N., Gordon, A. & Santra, R. Configuration-interaction-based time-dependent orbital approach for ab initio treatment of electronic dynamics in a strong optical laser field. Phys. Rev. A 74, 043420 (2006).
Pabst, S., Greenman, L., Mazziotti, D. A. & Santra, R. Impact of multichannel and multipole effects on the Cooper minimum in the high-order-harmonic spectrum of argon. Phys. Rev. A 85, 023411 (2012).
Pabst, S. et al. Theory of attosecond transient-absorption spectroscopy of krypton for overlapping pump and probe pulses. Phys. Rev. A 86, 063411 (2012).
Perelomov, A. M., Popov, V. S. & Terent’ev, M. V. Ionization of atoms in an alternating electric field. Sov. Phys. JETP 23, 924–934 (1966).
Ammosov, M. V., Delone, N. B. & Krainov, V. P. Tunnel ionization of complex atoms and of atomic ions in an alternating electromagnetic field. Sov. Phys. JETP 64, 1191–1194 (1986).
Yudin, G. L. & Ivanov, M. Y. Nonadiabatic tunnel ionization: looking inside a laser cycle. Phys. Rev. A 64, 013409 (2001).
Ott, C. et al. Lorentz meets Fano in spectral line shapes: a universal phase and its laser control. Science 340, 716–720 (2013).
Jurvansuu, M., Kivimäki, A. & Aksela, S. Inherent lifetime widths of Ar 2p−1, Kr 3d−1, Xe 3d−1, and Xe 4d−1 states. Phys. Rev. A 64, 012502 (2001).
Santra, R., Yakovlev, V. S., Pfeifer, T. & Loh, Z.-H. Theory of attosecond transient absorption spectroscopy of strong-field-generated ions. Phys. Rev. A 83, 033405 (2011).
Leone, S. R. et al. What will it take to observe processes in ‘real time’. Nat. Photon. 8, 162–166 (2014).
Karamatskou, A., Pabst, S. & Santra, R. Adiabaticity and diabaticity in strong-field ionization. Phys. Rev. A 87, 043422 (2013).
Schultze, M. et al. Controlling dielectrics with the electric field of light. Nature 493, 75–78 (2013).
Schultze, M. et al. Attosecond band-gap dynamics in silicon. Science 346, 1348–1352 (2014).
Cederbaum, L. S. & Zobeley, J. Ultrafast charge migration by electron correlation. Chem. Phys. Lett. 307, 205–210 (1999).
Breidbach, J. & Cederbaum, L. S. Migration of holes: formalism, mechanisms, and illustrative applications. J. Chem. Phys. 118, 3983–3996 (2003).
Kraus, P. M. et al. Measurement and laser control of attosecond charge migration in ionized iodoacetylene. Science 350, 790–795 (2015).
Timmers, H. et al. Polarization-assisted amplitude gating as a route to tunable, high-contrast attosecond pulses. Optica 3, 707–710 (2016).
Pabst, S. et al. XCID–The Configuration-Interaction Dynamics Package Rev. 1220 (CFEL, DESY, 2014).
Pabst, S. Atomic and molecular dynamics triggered by ultrashort light pulses on the atto-to picosecond time scale. Eur. Phys. J. 221, 1–71 (2013).
Chen, Y.-J., Pabst, S., Karamatskou, A. & Santra, R. Theoretical characterization of the collective resonance states underlying the xenon giant dipole resonance. Phys. Rev. A 91, 032503 (2015).
Santra, R., Dunford, R. W. & Young, L. Spin–orbit effect on strong-field ionization of krypton. Phys. Rev. A 74, 043403 (2006).
This material is based upon work supported by the National Science Foundation (NSF) (CHE-1361226) and the US Army Research Office (ARO) (W911NF-14-1-0383). Z.-H.L. acknowledges support from the Ministry of Education (MOE2014-T2-2-052) and the Agency for Science, Technology and Research (1223600008 and 1321202083). S.P. is funded by the Alexander von Humboldt Foundation and by the NSF through a grant to ITAMP.
The authors declare no competing financial interests.
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Sabbar, M., Timmers, H., Chen, YJ. et al. State-resolved attosecond reversible and irreversible dynamics in strong optical fields. Nature Phys 13, 472–478 (2017). https://doi.org/10.1038/nphys4027
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