S.P. Feofilov

Transient hole-burning and homogeneous linewidth of Eu3+ in sol-gel-produced corundum

In α-Al 2 O 3 , small-grain ceramics prepared by annealing of sol-gel-produced γ-Al 2 O 3 , it is possible to obtain trivalent rare earth ions at a single regular site despite the large difference in RE 3 and Al 3 + ionic radii. Transient spectral holes, generated by a redistribution of the population among the hyperfine levels of the two isotopes of Eu 3+ , were burned in the inhomogeneously broadened lineshape of the 7 F 0 - 5 D 0 transition of Eu 3+ . This observation gives additional evidence for the regular structure of Eu 3+ centers in small-grain corundum ceramics. The temperature-dependent hole broadening probably results from dephasing of electronic states by two-phonon Raman processes. The results are discussed together with earlier non-resonant fluorescence line narrowing results on the 5 D 0 - 7 F 1 transition, obtained by single frequency excitation of the 7 F 0 - 5 D 0 transition.