Optics CommunicationsSub-kilohertz optical linewidths of the 7F0 ↔ 5D0 transition in Y2O3:Eu3+R. M. Macfarlane, Robert M. ShelbyPublished Oct 1, 1981• 92 citationsPublisherDOI10.1016/0030-4018(81)90048-1