• Corpus ID: 118192813

Real-time evolution of a laser-dressed Helium atom: Attosecond-resolved two-color photoionization study

@article{Shivaram2011RealtimeEO,
  title={Real-time evolution of a laser-dressed Helium atom: Attosecond-resolved two-color photoionization study},
  author={Niranjan H. Shivaram and Henry Timmers and Xiao-Min Tong and Arvinder Singh Sandhu},
  journal={arXiv: Atomic Physics},
  year={2011}
}

• N. Shivaram, H. Timmers, +1 author A. Sandhu
• Published 30 July 2011
• Physics
• arXiv: Atomic Physics

Using extreme-ultraviolet attosecond-pulse-trains, we investigate the photoionization dynamics of a Helium atom in the presence of moderately-strong (~10^12 W/cm^2) femtosecond laser pulses. The electronic structure of a laser-dressed atom is traced in real-time through precision measurements of ion-yields and photo-electron angular distributions. Quantum interferences between photo-excitation paths are interpreted using the Floquet formalism. As the laser pulse intensity ramps on femtosecond timescales, we observe transitions between ionization channels mediated by different atomic resonances. The quantum phase of interfering paths is extracted for each channel and compared with simulations. Our results elucidate photoionization mechanisms in strong-fields and open the doors for photo-absorption/ionization control schemes.