Physical Review LettersSelf-Absorption and Trapping of Sharp-Line Resonance Radiation in RubyF. Varsanyi, Darwin L. Wood, ARTHUR L. SCHAWLOWPublished Dec 15, 1959• 115 citationsPublisherAbstractReceived 12 November 1959DOI:https://doi.org/10.1103/PhysRevLett.3.544©1959 American Physical SocietyDOI10.1103/physrevlett.3.544