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Two-photon-excited fluorescence spectroscopy of Rb atoms in a magneto-optical trap

Alan McLean1, Christian Drago2, Daniel Podos1, Chengyi Luo1, Caleb Brzezinski1, Ting-Wei Hsu1, J. E. Sipe2, and Ralph Jimenez1,*

  • *Contact author: rjimenez@jila.colorado.edu
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Phys. Rev. Applied 26, 034067 – Published 28 September, 2026

DOI: https://doi.org/10.1103/c8gq-zp19

Abstract

We report the results of two-photon-excited fluorescence (TPEF) measurements of the 5S1/2→5D5/2 transition of Rb85 and Rb87 cooled in a magneto-optical trap. We observe TPEF at excitation powers as low as 1  μW or fluxes as low as 2.98−0.94+1.37×1018  photons cm−2 s−1 (Rb85) and 3.31−1.33+2.21×1018  photons cm−2 s−1 (Rb87). Our results demonstrate that optically cooled Rb is a promising platform for observing sensitive two-photon spectral signatures at low photon fluxes.

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Phys. Rev. Applied 26, 034067– Published 28 September, 2026
  • Received 10 January 2026
  • Revised 4 June 2026
  • Accepted 7 July 2026
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