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

Published

April 6, 2007

Author(s)

Jason Stalnaker, Yann LeCoq, Tara M. Fortier, Scott A. Diddams, Christopher W. Oates, Leo W. Hollberg

Abstract

We apply direct frequency-comb spectroscopy, in combination with precision cw spectroscopy, to measure the 4s4_p³P₁ – 4s5s transition frequency in cold calcium atoms. An 657 nm ultrastable cw laser was used to excite atoms on the narrow (γ {approximately) 400 Hz)4s²¹S₀ – 4s4p ³P₁ clock transition, and the direct output of the frequency comb was used to excite those atoms from the 4s4p³P₁ state to the 4s5s³S₁ state. The resonance of the second stage was detected by observing a decrease in population of the ground state as a result of atoms being optically pumped to the meta-stable 4s4p³P_0,2 states. The 4s4p³P₁ – 4s5s³S₁ transition frequency is measured to be Ņ= 489 544 285 713(56) kHz; an improvement of almost four orders of magnitude over the previously measured value. In addition, we demonstrate spectroscopy on magnetically trapped atoms in the 4s4p³P₂ state.

Citation

Physical Review A (Atomic, Molecular and Optical Physics)

Volume

75

Pub Type

Journals

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Keywords

calcium, cold atoms, direct frequency comb spectroscopy, mode-locked lasers, optical frequency measurement

Citation

Stalnaker, J. , LeCoq, Y. , Fortier, T. , Diddams, S. , Oates, C. and Hollberg, L. (2007), Measurement of excited-state transitions in cold calcium atoms by direct femtosecond frequency-comb spectroscopy, Physical Review A (Atomic, Molecular and Optical Physics), [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=50486 (Accessed October 8, 2025)