Faraday spectroscopy in an optical lattice: A continuous probe of atom dynamics

Greg A. Smith, Souma Chaudhury, Poul S. Jessen

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


The linear Faraday effect is used to implement a continuous; measurement of the spin of a sample of laser-cooled atoms trapped in an optical lattice. One of the optical lattice beams serves also as a probe beam, thereby allowing one to monitor the atomic dynamics in real time and with minimal perturbation. A simple theory is developed to predict the measurement sensitivity and associated cost in terms of decoherence caused by the scattering of probe photons. Calculated signal-to-noise ratios in measurements of Larmor precession are found to agree with experimental data for a wide range of lattice intensity and detuning. Finally, quantum back-action is estimated by comparing the measurement sensitivity to spin projection noise, and shown to be insignificant in the current experiment. A continuous quantum measurement based on Faraday spectroscopy in optical lattices may open up new possibilities for the study of quantum feedback and classically chaotic quantum systems.

Original languageEnglish (US)
Pages (from-to)323-329
Number of pages7
JournalJournal of Optics B: Quantum and Semiclassical Optics
Issue number4
StatePublished - Aug 2003


  • Continuous quantum measurement
  • Laser cooling and trapping
  • Linear Faraday effect
  • Optical lattice

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Physics and Astronomy (miscellaneous)


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