Production of quasi-one-dimensional very-high- n Rydberg atoms

We demonstrate that strongly polarized quasi-one-dimensional very-high-n (potassium) Rydberg atoms can be produced by photoexcitation of selected Stark states in the presence of a weak dc field. Calculations show that, for m=0 states, significant photoexcitation occurs only in the vicinity of the Stark-shifted s, p, and d levels, and that those states located near the Stark-shifted d level have sizable polarizations. These predictions are confirmed by experiment. The degree of polarization of the product states is analyzed by studying differences in their ionization characteristics when subject to short pulsed electric fields applied parallel and antiparallel to the dc field.