Observation of Quantum Jumps

Abstract

We have recorded the laser-excited resonance fluorescence of one to three ${\mathrm{Ba}}^{+}$ ions and observed Bohr's "quantum jumps" when an ion decayed to the metastable $^{2}D_{\frac{5}{2}}$ state, suddenly quenching its fluorescence. Most of the jumps mark Raman-Stokes scattering from the $^{2}S_{\frac{1}{2}}$ and $^{2}D_{\frac{3}{2}}$ levels.