We performed laser spectroscopy of
In+ ions stored in a radio-frequency trap. The 5
s2 1S0\ensuremath{\rightarrow}5s5p
3P1 transition at 230.6 nm was excited and its hyperfine splitting and isotope shift have been measured. The lifetime of the
3P1 state was measured using intensity modulated laser excitation: \ensuremath{\tau}
(3P1)=0.44(4) \ensuremath{\mu}s. A single indium ion was laser cooled using this intercombination line and dark periods in the fluorescence were observed when the metastable
3P0 state was populated by a magnetic dipole decay from
3P1. The radiative lifetime of the forbidden transition
3P0${\ensuremath{\rightarrow}}^{1}$
S0 was determined from the duration of the dark periods: \ensuremath{\tau}
(3P0)=0.14(2) s. This value is compared to calculations based on perturbation theory. Prospects for an optical frequency standard using the narrow 5
s2 1S0\ensuremath{\rightarrow}5s5p
3P0 resonance at 236.5 nm of a single laser-cooled indium ion are discussed.
We performed laser spectroscopy of
In+ ions stored in a radio-frequency trap. The 5
s2 1S0\ensuremath{\rightarrow}5s5p
3P1 transition at 230.6 nm was excited and its hyperfine splitting and isotope shift have been measured. The lifetime of the
3P1 state was measured using intensity modulated laser excitation: \ensuremath{\tau}
(3P1)=0.44(4) \ensuremath{\mu}s. A single indium ion was laser cooled using this intercombination line and dark periods in the fluorescence were observed when the metastable
3P0 state was populated by a magnetic dipole decay from
3P1. The radiative lifetime of the forbidden transition
3P0${\ensuremath{\rightarrow}}^{1}$
S0 was determined from the duration of the dark periods: \ensuremath{\tau}
(3P0)=0.14(2) s. This value is compared to calculations based on perturbation theory. Prospects for an optical frequency standard using the narrow 5
s2 1S0\ensuremath{\rightarrow}5s5p
3P0 resonance at 236.5 nm of a single laser-cooled indium ion are discussed.
Single laser-cooled ions in radiofrequency traps can serve as the basis for highly stable optical frequency standards. Here we present recent results on In+, using the 1S0 yields 3P0 line at 236.5 nm wavelength as the clock transition. This resonance has a natural linewidth of only 0.82 Hz and systematic shifts should be controllable at the mHz level. A single indium ion is stored in a miniature Paul- Straubel trap and laser cooled to a temperature of about 100 (mu) K. The clock transition is excited using a frequency quadrupled 946 nm Nd:YAG laser. A fractional resolution of 1.3 (DOT) 10-13 has been achieved so far (linewidth of 170 Hz at 1267 THz). The absolute optical frequency of the clock transition has been measured with an uncertainty being less than 3 (DOT) 10-13 using a frequency chain and a methane-stabilized HeNe laser that was calibrated with a cesium clock.