Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 1: Posters Monday (Cluster, Atoms in Fields)

A 1.23: Poster

Montag, 2. April 2001, 12:30–15:00, AT3

Field Ionisation of Rydberg Atoms with THz Radiation — •Thorsten Harter, Peter Uhd Jepsen, and Hanspeter Helm — Universität Freiburg, Fakultät für Physik, Hermann-Herder-Str. 3, 79104 Freiburg i.Br.

Using a tuneable ns-dye laser, thermal Rubidium atoms are selectively excited to Rydberg states of quantum numbers between n=35 and n=55. After creation of the Rydberg atoms and before their ionisation by a pulsed ramp field, the atoms are exposed to two correlated THz-pulses with variable time delay. Subpicosecond THz-pulses are generated by illuminating two biased GaAs emitters with a fs-laser. In this way it is possible to perform pump-probe experiments such as redistributing the original state into a wave packet containing several different Rydberg states as well as monitoring the temporal evolution of the wave packet in its classical Kepler orbit.

Our further goal is to impart upon a Rydberg electron a well known kick by a unipolar THz-pulse. This kick is used to lift the Rydberg electron from its bound state into the continuum. By the use of a sub-meV electron spectrometer it should be possible to gain direct insight into the instantaneous momentum of the bound electron.

Research supported by the DFG (SFB 276 TPC14)