Luminescence properties of MgF2:Yb2+ at high hydrostatic pressure

Hydrostatic pressures of up to 200 kbar have been employed to influence the spectroscopic properties of MgF2 doped with divalent ytterbium. MgF2:Yb2+ exhibits a broad band emission peaked at 485 nm related to the 4f135d1→4f14 transition of Yb2+. At pressures between ambient and 92 kbar, a red-shift of the luminescence maximum was observed, whilst simultaneously the decay time of the emission gradually decreased. Abrupt changes were observed in the emission spectra at 92 and 145 kbar which were related to the phase transitions of the host lattice induced by pressure. It has been shown that pressure does not change energetic structure of three first excited states of Yb2+ in the rutile phase but is responsible for an increase in the probability of non-radiative depopulation of the first excited triplet state from the 4f135d1 electronic configuration.