Diagnostics of a Diluted Ultracold Plasma Using the Autoionization Effect of Rydberg States of Ca-40 Atoms

摘要

A sensitive method to study a dilute ultracold plasma based on the autoionization resonances of Rydberg atoms is demonstrated. Ultracold Ca-40 Rydberg atoms are prepared in a continuously operating magneto-optical trap. A method that allows the detection of the plasma with ion and electron densities below 10(9) m(-3) is shown. Experimental studies of resonances at the two-photon Rydberg transition have been carried out using 672 and 798 nm resonant laser beams. The autoionization resonance is observed during fluorescence of single-charged Ca-40 ions at a wavelength of 397 nm. The dependence of the amplitude of autoionization resonance on the density of ions in the continuously generated ultracold plasma is obtained.