Photon avalanche up-conversion in holmium doped fluoride glasses

摘要

Photon avalanche green up-conversion emission centered at 545 nm has been observed in Ho(sup 3+) doped and Ho(sup 3+), Tm(sup 3+) co-doped ZrF(sub 4)-based fluoride glasses when excited near 585 nm which is off resonance with any ground state absorption bands of either Ho(sup 3+) or Tm(sup 3+) ions. Detailed spectral measurements and analysis suggest that the 545 nm emission occurs from the (sup 5)S(sub 2),(sup 5)F(sub 4) states of Ho(sup 3+) that are populated by excited state absorption from the (sup 5)I(sub 7) state of Ho(sup 3+). Strong cross-relaxation that efficiently populates the (sup 5)I(sub 7) state makes the photon avalanche process possible in this system.