Ionization of Rydberg Atoms in THz-Laser Fields at the Transition from Low to High Scaled Frequencies

Experimental and simulated threshold laser fields for Rydberg state Xe atom photoionization vs. effective principal quantum number

Sven Ring, Burkhard Schmidt, and Helmut Baumgärtel

We have studied the ionization of Rydberg-excited xenon atoms in THz-laser fields and by quantum dynamical calculations. The experimental threshold laser field strength for 10% ionization probability follows an n*-1.68 (ω/2π=1.04 THz) dependence (n* effective principal quantum number) with additional weak resonance structures and shows that ionization does not occur by a Landau-Zener mechanism. At scaled frequencies of Ω = 0.71 to 5.6 the simulated threshold fields for ionization in oscillatory fields show a dependence on the principal quantum number n of n-4.1 to n-1.35.

Eur. Phys. J. D 3 (2), 155-158 (1998)