Trap Effect in Spctral Hole Burning of Sm2+ Doped Crystals

Abstract

Since the first observation of persistent photon gated spectral hole burning in BaFCl:Sm2+ at liquid helium temperature[1], the successful improvement on this material has been performed in our laboratory by adding bromine and alkline earth metals in the melt to form MyM'1-yFClxBr1-x:Sm (M,M'=Mg, Ca, Sr, Ba; x,y=0-1) system, in which the inhomogeneous line is broadened significantly[2-5] and room temperature hole burning is realized [6]. The hole burning mechanism is found to be photoionization of Sm2+ followed by electron trapping[1]. A kind of principal electron trap is considered to be Sm3+[1], which brings about hole refilling in the holes burnt formerly as burning the next hole because the generated Sm3+ corresponding to the former holes can trap electrons again released in the next hole burning[7]. That means, writing will erase the stored information. To avoiding this effect, introducing an other kind of trap different from Sm3+ for hole burning is necessary In the present paper, we report the results of hole burning in Sm singly doped and Sm, Yb doubly doped SrFCl crystals at 77K and room temperature. Two different trap effects in hole burning are observed and discussed.