Observation of a nonclassical Berrys phase for the photon

Paul G. Kwiat, Raymond Y. Chiao

Research output: Contribution to journalArticlepeer-review


Coincidence detection of photon pairs produced in parametric fluorescence, in conjunction with a Michelson interferometer in which one member of each pair acquired a geometrical phase due to a cycle in polarization states, has allowed the first observation of Berrys phase at the single-photon level. We have verified that each interfering photon was essentially in an n=1 Fock state, by means of a beam splitter following the interferometer combined with a triple-coincidence technique. The results can be interpreted in terms of a nonlocal collapse of the wave function.

Original languageEnglish (US)
Pages (from-to)588-591
Number of pages4
JournalPhysical review letters
Issue number5
StatePublished - 1991
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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