Atomic Engineering: Production of Very-High-n Quasi-1D Atoms

Quasi-one-dimensional (quasi-1D) atoms can be produced by photoexciting selected Stark states in the presence of a weak dc field. For $n\ge $500, such direct excitation of quasi-1D atoms becomes problematic because stray fields and effective laser linewidths lead to creation of a range of Stark states with no preferred orientation. We show here that very-high-$n$ quasi-1D atoms can be produced by a multi-step process in which lower-$n$ ($n\sim $350) quasi-1D atoms are first produced. The excited electron is then localized in phase space near the outer classical turning point at which time it is transferred to a highly-elongated very-high-$n$ orbit using a half-cycle pulse (HCP). This leads to population of a broad distribution of final $n$states centered at $n\sim $580 which it is shown can be dramatically narrowed by subsequent application of further HCPs. The factors that govern the final $n$ distribution are discussed with the aid of classical simulations. The availability of very-high-$n$ quasi-1D atoms allows the dynamics of the periodically kicked atom to be examined at high scaled frequencies, $\nu _0 \approx 15$. Novel behavior, such as local increases in survival probability with increasing number of kicks, is observed.