The luminescence properties of rare-earth ions in natural fluorite

For the first time, the luminescence properties of Pr3?, Nd3? and Tm3? and Yb3? ions in fluorite crystal have been obtained by steady-state measurements. In addition, the luminescence spectra of Ce3?, Sm2?, Sm3?, Dy3?, Er3? and Yb3? were measured. It was pointed out that kexc. = 415 nm is most suitable for measuring the Ho3? emission beside the Er3?. The emission of trivalent holmium and erbium ions was measured independently using time-resolved measurements and tentative assignment of luminescence lines to C3v and C4v symmetry sites was proposed. Besides for natural fluorite crystal, the transitions between Stark energy levels of lanthanide ions were presented