B. Appasamy et al., QUANTIZED INFRARED-OPTICAL TRIPLE-RESONANCE ON A SINGLE COLD BARIUM ION, Applied physics. B, Lasers and optics, 60(5), 1995, pp. 473-477
A single trapped and cooled Ba+ ion is irradiated by resonant visible
light (493, 650 nm) alternating with light at 1.76 mu m which may exci
te the ion to its D-2(5/2) metastable state. The (absence of) visible
resonance scattering probes the excitation, tuning spectra of which sh
ow vibrational sidebands that characterize the ion's temperature. Obse
rved values as low as 120 mu K, one-eighth the Doppler limit, are ascr
ibed to electronic Raman cooling by the visible light. Tuning spectra
of the events of stimulated deexcitation indicate ion heating by the I
R interaction. The results demonstrate the feasibility of vibrational
spectrometry on a single particle that oscillates in a potential well,
forming a quasi-molecule.