EXCITED-STATE ABSORPTION IN ZNWO(4) CRYSTAL

We report the first measurement of Excited-State Absorption (ESA) in a zinc tungstate (ZnWO4) crystal. The ESA is assigned to the 2e --> 4t2 transitions and, in the simplest picture, can be related to the 10Dq energy in T(d) symmetry. The breadth and height of the ESA spectrum, compared with stimulated emission spectrum, precludes any possibility of laser action in this material. The very high strength of ESA transitions suggests a triplet character of the terminal ESA term, originating in (t5/1,4t2) configuration, and breaking the Laporte selection rule. The latter is consistent with considerable contribution of p-orbitals of the ligands and the tungsten ion in the terminal ESA state.