Electron transition process of 5D2→7F0 of Sm2+ in spectral hole-burning

Materials of MyM’1-yFClxBr1-x:Sm2+ have been widely applied in spectral hole-burning since the first observation of persistent spectral hole-burning in BaFCl:Sm2+ at 2K was reported by A. Winnaker, etc. in 1985[1]. From then on, hole-burning in BaFCl0.5Br0.5:Sm2+ at 77K[2] in SrFCl and Mg0.5Sr0.5FCl0.5Br0.5:Sm2+ at room temperature[3, 4] were reported. Room temperature hole-buring of Sm2+ in fluorohafnate glasses[5,6] were reported in recent years also. These materials are of potential use in high temperature hole- burning. But comparing to organic materials, they have lower hole- burning efficiency and narrower inhomogenous line width. In order to apply spetral hole- buring in frequency domain optical storage, it is important to improve these materials.