ADIABATIC STABILIZATION - OBSERVATION OF THE SURVIVING POPULATION

Photoionization of the circular 5g Rydberg state in neon by an intense subpicosecond light pulse is studied. Both the photoionization yield and the remaining population are measured. We find that the photoioniz ation yield does not increase when the pulse peak intensity is increas ed above 60 TW/cm(2), and that a large fraction of the population rema ins in the 5g state instead. These results are consistent with predict ions for adiabatic stabilization. The measurements are done using a se quence of three laser pulses. The first laser pulse excites the circul ar 5g state from the neon ground state, the second pulse is the intens e light pulse that leads to the ionization (or lack thereof due to sta bilization) we actually study, and the third pulse is a low-intensity high-fluence pulse ionizing all of the remaining 5g population. The ph otoionization yields of these three pulses an detected and separated b y electron spectroscopy.