Measurement of excited-state transitions in cold calcium atoms by direct femtosecond frequency-comb spectroscopy

Abstract

We apply direct frequency-comb spectroscopy, in combination with precision cw spectroscopy, to measure the ${4s4p}^3{P}_1\to {4s5s}^3{S}_1$ transition frequency in cold calcium atoms. A 657 nm ultrastable cw laser was used to excite atoms on the narrow ($\gamma \sim 400$ Hz) ${4{\mathrm{s}}^2}^1{S}_0\to {4s4p}^3{P}_1$ clock transition, and the direct output of the frequency comb was used to excite those atoms from the ${4s4p}^3{P}_1$ state to the ${4s5s}^3{S}_1$ state. The resonance of this second stage was detected by observing a decrease in population of the ground state as a result of atoms being optically pumped to the metastable ${4s4p}^3{P}_{0,2}$ states. The ${4s4p}^3{P}_1\to {4s5s}^3{S}_1$ transition frequency is measured to be $\nu =489544285713(56)$ kHz; which is an improvement by almost four orders of magnitude over the previously measured value. In addition, we demonstrate spectroscopy on magnetically trapped atoms in the ${4s4p}^3{P}_2$ state.

4 pages 5 figures

References in corpus (1)

• Kilohertz-resolution spectroscopy of cold atoms with an optical frequency comb

Cited by in corpus (1)

• Signatures of the Anderson localization excited by an optical frequency comb