Latest developments of bulk crystals and thin films of rare-earth doped CaF2 for laser applications

Several CaF2 single crystals doped with trivalent rare-earth ions have been grown in the recent years in the form of bulk crystals by using the Bridgman method and in the form of thin films by using the MBE and LPE techniques. The spectroscopic, gain and laser properties of these crystals doped with Pr3+, on the one hand, and with Yb3+, Tm3+ or Er3+ ions, on the other hand, have been studied and are reviewed here for their laser potentials in the red and in the infrared spectral domains, respectively.