Physical Review Research (Dec 2019)

Observation of a large, resonant, cross-Kerr nonlinearity in a cold Rydberg gas

  • Josiah Sinclair,
  • Daniela Angulo,
  • Noah Lupu-Gladstein,
  • Kent Bonsma-Fisher,
  • Aephraim M. Steinberg

DOI
https://doi.org/10.1103/PhysRevResearch.1.033193
Journal volume & issue
Vol. 1, no. 3
p. 033193

Abstract

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We report the experimental observation of a cross-Kerr nonlinearity in a free-space medium based on resonantly excited, interacting Rydberg atoms and electromagnetically induced transparency. The nonlinearity is used to implement cross-phase modulation between two optical pulses. The nonlinear phase written onto the probe pulse is measured to be as large as 8 mrad per nanowatt of signal power, corresponding to a χ^{(3)} of 10^{−8}m^{2}/V^{2}. Potential applications range from optical quantum information processing to quantum nondemolition measurement of photon number.