Measurement of the enhancement of the radiative decay of atoms near an optical nanofiber

ORAL

Abstract

The spontaneous decay rate of an atom near a dielectric is modified by the induced dipole and by a change in the modes of the vacuum electromagnetic field. This decay rate directly determines the coupling strength between an atom and the guided mode of a waveguide. We measure the spontaneous decay rate of the $5P_{3/2}$ state in $^{87}$Rb atoms near a silica optical nanofiber with a diameter of 500 nm that allows only the fundamental $HE_{11}$ mode at 780 nm. We excite a cloud of cold atoms with short, near-resonant laser pulses and use time-correlated single photon counting to directly measure the spontaneous emission into free space and into the nanofiber guided mode. Comparing the two decay constants yields a $\sim4\%$ enhancement due to the nanofiber, consistent with theory.

*This work is supported by ARO MURI award W911NF0910406 and the NSF Physics Frontier Center at the JQI

–

Authors

  • P. Solano

    • Joint Quantum Institute, Dept. of Physics, UMD and NIST, College Park, MD 20742, USA

  • J.A. Grover

    • Joint Quantum Institute, Dept. of Physics, UMD and NIST, College Park, MD 20742, USA

  • L.A. Orozco

    • Joint Quantum Institute, Dept. of Physics, UMD and NIST, College Park, MD 20742, USA

  • S.L. Rolston

    • Joint Quantum Institute, Dept. of Physics, UMD and NIST, College Park, MD 20742, USA

  • H.J. Carmichael

    • Dept. of Physics, University of Auckland, Auckland 1010, New Zealand