Room-temperature persistent hole burning of Sm(2+) in oxide glasses.

Persistent spectral hole burning in Sm2+-doped borate glasses is observed at room temperature. The possible number of holes is approximately five times larger than in halide glass systems because of the larger inhomogeneous linewidth and smaller hole width of borate glass. In this system the photoionization of trapping electrons other than Sm ions at a site is likely to be dominant because of the absence of an antihole adjacent to the hole.