THE SPECTRUM OF SINGLE-ATOM RESONANCE FLUORESCENCE

The emission spectrum of the bichromatically excited resonance fluores cence of a single atomic particle, i.e. of a permanently trapped and c ooled Ba+ ion has been recorded. It shows up to five peaks, two of the m partially resolved, in agreement with fluorescence spectra of three- level atoms calculated from sets of parameters separately measured fro m recorded excitation spectra of the integrated fluorescence.