KMgF

3

which was typical cubic perovskite structure

was ideal material for searching for new solid state laser because of its several advantages: good homogenous optics

high thermal stability

low melting point

anisotropy and high optical transparency etc.Due to the broad forbidden band and weak crystal field intensity

KMgF

3

could stabilize low-valence rare earth ions

which

c

ould be used to further study refine spectra structure of these rare earth ions.Using a traditional high temperature solid state reaction

mild hydrothermal and bridgman stockbarger method

the KMgF

3

:Eu

2+

samples was synthesized.In the hydrothermal and single crystal samples

the 420nm emission peak besides the emission of Eu

2+

at 359.5nm was observed.After the sample was annealed

the emission intensity at 420nm lowered about 30 times than that before annealing

but there still was the weak emission peak at 420nm.We drew a conclusion that the 420nm emission peak resulted from main color center and trace oxygen center.Combining the intensity change of theEu

2+

emission at 359.5nm in KMgF

3

:Eu

2+

sample annealed before and after

we proved that the energy transfer fromEu

2+

to color centers occurred.In addition

the relative oxygen content in crystal was calculated by means of the absorption spectra data.