Optical absorption

emission and excitation spectra

lifetime of

5

S

2

state from 10K to 660K for Ho

3+

ions in fluoride glass and the Raman spectrum of fluoride glass were measured. The radiative transition probabilities of Ho

3+

in fluoride glass were calculated from its absorption spectrum on the basis of Judd-Ofelt theory. The nonradiative transition probabilities of

5

S

2

state from 10K to 660K were determined by the calculated radiative transition probability and the mesured lifetimes of

5

S

2

state at different temperatrues. With phonon energy determined from Raman spectrum

it is found that if only one kind of phonon were considered there could be no way to conform with the experimental results

while if phonons with two different frequncies

as well as the influnce of Huang’s factor are taken into account

fairly good fitting could be obtained.The Huang’s factor is estimated from the fitting of the theory to the experimental results. The effect of Huang’s factor on nonradiative transition rates is discussed.