Physical Review LettersObservation of Degenerate Stimulated Four-Photon Interaction and Four-Wave Parametric AmplificationRobert L. Carman, R. Y. Chiao, Paul L. KelleyPublished Dec 26, 1966• 149 citationsPublisherAbstractReceived 14 November 1966DOI:https://doi.org/10.1103/PhysRevLett.17.1281©1966 American Physical SocietyDOI10.1103/physrevlett.17.1281