Dipolar Rydberg-atom gas prepared by adiabatic passage through an avoided crossing

TL;DR

This paper demonstrates a method to create a cold gas of highly dipolar Rydberg atoms by adiabatically passing through an avoided crossing, with analysis supported by experiments and simulations.

Contribution

It introduces a technique to produce and analyze a dipolar Rydberg-atom gas via adiabatic passage through an avoided crossing, including state-selectivity and collision effects.

Findings

Successful preparation of a dipolar Rydberg-atom gas.

Observation of state-selective behavior due to $m$-mixing collisions.

Numerical simulations support the experimental results.

Abstract

The passage of cold cesium 49S$_{1/2}$ Rydberg atoms through an electric-field-induced multi-level avoided crossing with nearby hydrogen-like Rydberg levels is employed to prepare a cold, dipolar Rydberg atom gas. When the electric field is ramped through the avoided crossing on time scales on the order of 100~ns or slower, the 49S$_{1/2}$ population adiabatically transitions into high-\emph{l} Rydberg Stark states. The adiabatic state transformation results in a cold gas of Rydberg atoms with large electric dipole moments. After a waiting time of about $1~\mu$s and at sufficient atom density, the adiabatically transformed highly dipolar atoms become undetectable, enabling us to discern adiabatic from diabatic passage behavior through the avoided crossing. We attribute the state-selectivity to $m$-mixing collisions between the dipolar atoms. The data interpretation is supported by numerical simulations of the passage dynamics and of binary $m$-mixing collisions.