Applied Physics LettersCOHERENT OSCILLATIONS FROM Tm3+, Ho3+, Yb3+ and Er3+ IONS IN YTTRIUM ALUMINUM GARNETL. F. Johnson, J. E. Geusic, LeGrand G. Van UitertPublished Sep 1, 1965• 201 citationsPublisherDOI10.1063/1.1754339