TY - GEN
T1 - Observing the real-time evolution of helium atoms in a strong laser field
AU - Shivaram, Niranjan
AU - Timmers, Henry
AU - Tong, Xiao Min
AU - Sandhu, Arvinder
N1 - Funding Information:
This work was supported by NSF grant PHY-0955274.
PY - 2012
Y1 - 2012
N2 - The interaction of a strong laser field with an atom significantly modifies its atomic structure. Such an atom can be modeled using the Floquet theory in which the atomic states are described by Floquet states composed of several Fourier components. We use high-order harmonics present in extreme-ultraviolet (XUV) attosecond pulse trains (APTs) to create excited states in infra-red(IR) laser dressed He atoms which are ionized by the dressing laser field itself. The quantum interference between different components of the Floquet states leads to oscillation in the ion yield as a function of XUV-IR time delay. We measure the phase of this quantum interference process through the phase of the ion yield signal which allows us to follow the evolution of the dressed atom, in real-time, as the intensity of the IR field is varied.We observe a transition from a 5p Floquet state dominated ionization to a 2p Floquet state dominated ionization with increasing IR intensity.
AB - The interaction of a strong laser field with an atom significantly modifies its atomic structure. Such an atom can be modeled using the Floquet theory in which the atomic states are described by Floquet states composed of several Fourier components. We use high-order harmonics present in extreme-ultraviolet (XUV) attosecond pulse trains (APTs) to create excited states in infra-red(IR) laser dressed He atoms which are ionized by the dressing laser field itself. The quantum interference between different components of the Floquet states leads to oscillation in the ion yield as a function of XUV-IR time delay. We measure the phase of this quantum interference process through the phase of the ion yield signal which allows us to follow the evolution of the dressed atom, in real-time, as the intensity of the IR field is varied.We observe a transition from a 5p Floquet state dominated ionization to a 2p Floquet state dominated ionization with increasing IR intensity.
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U2 - 10.1007/978-3-642-28948-4_34
DO - 10.1007/978-3-642-28948-4_34
M3 - Conference contribution
AN - SCOPUS:84903837642
SN - 9783642289477
T3 - Springer Proceedings in Physics
SP - 203
EP - 207
BT - Multiphoton Processes and Attosecond Physics - Proceedings of the 12th Int. Conference on Multiphoton Processes, ICOMP 2011 and the 3rd International Conference on Attosecond Physics, ATTO 2011
PB - Springer Science and Business Media, LLC
T2 - 12th International Conference on Multiphoton Processes, ICOMP 2011 and the 3rd International Conference on Attosecond Physics, ATTO 2011
Y2 - 3 July 2011 through 8 July 2011
ER -