LASER COOLING AND QUANTUM JUMPS OF A SINGLE INDIUM ION

We performed laser spectroscopy of In+ ions stored in a radio-frequency trap. The 5s(2 1) S-0-->5s5p P-3(1) transition at 230.6 nm was excited and its hyperfine splitting and isotope shift have been measured. The lifetime of the P-3(1) State was measured using intensity modulated laser excitation: tau(P-3(1)) = 0.44(4) mu s. A single indium ion was laser cooled using this intercombination line and dark periods in the fluorescence were observed when the metastable P-3(0) State was populated by a magnetic dipole decay from P-3(1). Th, radiative lifetime of the forbidden transition P-3(0)-->S-1(0) was determined from the duration of the dark periods: tau(P-3(0)) = 0.14(2) s. This value is compared to calculations based on perturbation theory. Prospects for an optical frequency standard using the narrow 5s(2 1) S-0-->5s5p P-3(0) resonance at 236.5 nm of a single laser-cooled indium ion are discussed.