We report what is to our knowledge the first Dopplerless high-resolution optical spectroscopy based on unperturbed atoms left nearly at rest when a vapor cell magneto-optic trap is switched off. A λ = 285 nm beam excited the 3s → 5p transition in our sample of laser trapped/cooled Na atoms from which we collected fluorescence. Excited-state 52P3/2 and 52P1/2 hyperfine interaction constants are derived with 4- and 47-fold increases, respectively, in accuracy. Future prospects for vapor-cell-based optical spectroscopy and frequency standards are considered.
We report on cw measurements of probe beam absorption and four-wave-mixing spectra in a
85Rb magneto-optical trap taken while the trap is in operation. The trapping beams are used as pump light. We concentrate on the central feature of the spectra at small pump-probe detuning and attribute its narrow resonant structures to the superposition of Raman transitions between light-shifted sublevels of the ground atomic state and to atomic recoil processes. These two contributions have different dependencies on trap parameters and we show that the former is inhomogeneously broadened. The strong dependence of the spectra on the probe-beam polarization indicates the existence of large optical anisotropy of the cold-atom sample, which is attributed to the recoil effects. We point out that the recoil-induced resonances can be isolated from other contributions, making pump-probe spectroscopy a highly sensitive diagnostic tool for atoms in a working magneto-optical trap.
We describe an experiment which demonstrates the feasibility of trapping significant quantities of short-lived radioactive atoms with laser light. A thermal beam of 22.5 sec half-life
21Na atoms was produced on-line at the LBL 88'' Cyclotron. After decelerating the beam using a Zeeman-tuned slowing technique we stored about 4\ifmmode\times\else\texttimes\fi{}
103 21Na atoms in a magneto-optical trap. The number of trapped atoms is large enough to be used in experimental studies of the beta decay of
21Na. The basic method can be adapted for other rare isotopes.