On the emission and excitation spectrum of the NIR laser center in Cr:YAG

Abstract

We use a tunable narrowband laser operating in the region 1.1–1.3 μm to probe the excitation spectrum of the NIR laser center in Cr doped yttrium aluminum garnet (YAG) at low temperatures. Our results reveal that the sharp emission bands observed at low temperatures around 1.28 μm are true electronic origins. This is in contrast to previous interpretations of this luminophore in which these sharp bands have been interpreted as false origins built on a zero phonon line supposed, but not observed, to lie midway between the 1.28 μm bands in emission and a sharp “false origin” absorption band at 1.125 μm. We discuss the possible nature of this luminophore in light of these new results.