Physical Review LettersInfrared Quantum Counter Action in Pr-Doped Fluoride LatticesM. R. Brown, W. A. ShandPublished Oct 15, 1963• 33 citationsPublisherAbstractReceived 20 September 1963DOI:https://doi.org/10.1103/PhysRevLett.11.366©1963 American Physical SocietyDOI10.1103/physrevlett.11.366