Survival of atoms in strong microwave fields

Thomas F. Gallagher

I. Ia. Bersons

Alexandr Arakelyan, Türker Topçu, F. Robicheaux +1 more

When atoms are exposed to intense laser or microwave pulses, $\ensuremath{\sim}10%$ of the atoms are found in Rydberg states subsequent to the pulse, even if it is far more intense than required for static field ionization. The optical spectra of the surviving Li atoms in the presence of a 38-GHz microwave field suggest how atoms survive an intense pulse. The spectra exhibit a periodic train of peaks 38 GHz apart. One peak is just below the limit, and with a 90-V/cm field amplitude the train extends from 300 GHz above the limit to 3000 GHz below it. The spectra and quantum-mechanical calculations imply that the atoms survive in quasistable states in which the Rydberg electron is in a weakly bound orbit infrequently returning to the ionic core during the intense pulse.

Günter Ludyk

Eugene Oks, T. Uzer

The multiphoton ionization of hydrogen in strong parallel microwave and static fields is a fundamental problem of great complexity which has been the subject of recent experimental and theoretical studies. We show that the superposition of an additional field, namely a static, relatively weak magnetic field, results in rapid oscillations of the ionization survival probability. These rapid oscillations can be used as a very sensitive method for measuring weak magnetic fields.

Igor I Sobel'man