The mid-IR spectroscopic properties of
Er3+ doped low-phonon
CsCdCl3 and
CsPbCl3 crystals grown by the Bridgman technique have been investigated. Using optical excitations at
∼800nm and
∼660nm , both crystals exhibited IR emissions at
∼1.55 ,
∼2.75 ,
∼3.5 , and
∼4.5µm at room temperature. The mid-IR emission at 4.5 µm, originating from the
4I9/2→4I11/2 transition, showed a long emission lifetime of
∼11.6ms for
Er3+ doped
CsCdCl3 , whereas
Er3+ doped
CsPbCl3 exhibited a shorter lifetime of
∼1.8ms . The measured emission lifetimes of the
4I9/2 state were nearly independent of the temperature, indicating a negligibly small nonradiative decay rate through multiphonon relaxation, as predicted by the energy-gap law for low-maximum-phonon energy hosts. The room temperature stimulated emission cross sections for the
4I9/2→4I11/2 transition in
Er3+ doped
CsCdCl3 and