Charge laser action from

The MCI2 (M = Ca, Sr, and Ba) crystals are ideal candidates for studies of the spectroscopic properties of Tm " ions. First, no charge-compensation defects are required after thulium ions are introduced into these hosts. Second, there is reliable experimental information about the absorption/emission spectra of these materials [2-8]. Moreover, the earth-alkaline halides are also important from an application point of view because the laser action has been achieved in CaF2 Tm [9]. The spectra of Tm " were modeled in our earlier publication [10]. 

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