Influence of an electric field on Rydberg nD states of cold lithium atoms

Abstract

Influence of a weak electric field on the coherent Rydberg resonances was studied on two-photon transitions 2S–nD by recording the resonance fluorescence of lithium atoms in a magneto-optical trap. It was observed that an isolated spectral line 2P–nD transferred to the spectral band width growing with a principal number n (or an electric field E). It was shown that the frequency tuning of a resonant radiation on the left (right) edge of the band allows to create a gas of Rydberg atoms with fixed and large dipole moments d ∝ ea 0 n 2 (e is the elementary charge, a 0 is the Bohr radius), oriented against (along) the electric field. The radiation frequency was tuned on the center of the band would produced atomic states with zero dipole moments, but with a big contribution of states with maximum angular momentum quantum number l ~ n.