Electro-optic sampling of near-infrared waves, and attosecond polarization spectroscopy (Dr. Karpowicz) / Laser spectroscopy of pionic and antiprotonic helium atoms (Dr. Hori)

  • Double Feature!
  • Date: Apr 19, 2016
  • Time: 02:30 PM - 04:00 PM (Local Time Germany)
  • Speaker: Dr. N. Karpowicz, MPQ, Attosecond Physics Division / Dr. M. Hori, MPQ, Laser Spectroscopy Division
  • Room: Herbert Walther Lecture Hall
  • Host: MPQ
abstracts...

Electro-optic sampling of near-infrared waves, and attosecond polarization spectroscopy (Dr. Karpowicz)
Direct access to the electric field waveform of near-infrared and visible light allows for a detailed view of light-matter interaction on the femtosecond or even attosecond time scale. Two techniques, attosecond streaking and electro-optic sampling, are able to provide this access, the latter being adopted from the THz frequency range and recently improved in temporal resolution to the point where field oscillations at 240 THz can be observed. I will show how this has enabled direct reconstruction of the time-dependent nonlinear polarization of materials interacting with strong laser fields and the observation of sub-cycle energy exchange between a laser field and solid and atomic targets. This approach to attosecond physics is capable of providing sub-femtosecond time resolution without requiring the sample under study to interact with extreme ultraviolet radiation, presenting a number of new opportunities for experiments with extreme temporal resolution.

Laser spectroscopy of pionic and antiprotonic helium atoms (Dr. Hori)
The pion is the lightest and most long-lived meson consisting of two valance quarks. Metastable pionic helium is a heretofore hypothetical three-body atom composed of a helium nucleus, an electron in the 1s-state, and a pion in a Rydberg state. In this talk, we describe the latest efforts at achieving the first laser spectroscopy of this atom using the Ring Cyclotron facility of the Paul Scherrer Institute.Antiprotonic helium is a “cousin” of pionic helium, wherein an antiproton replaces the pion. We recently attempted to cool down these atoms to cryogenic temperatures by buffer gas cooling. By measuring the transition frequencies very precisely, the antiproton-to-electron mass ratio can be precisely determined, and compared with the proton-to-electron value. The recent results of experiments carried out at the Antiproton Decelerator facility of CERN will be presented.

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