Optical Parameters of NaY(WO4)2 Crystals Doped with Pr and Ho

Rare-earths (Pr, Ho) doped double tungstates NaY(WO 4 ) 2 crystals were prepared by using Czochralski (CZ) pulling method. Their absorption spectra have been measured in the region 300-2000nm at room temperature. A band gap of eigentransition of 3.92eV was obtained. The three phenomenological parameters were calculated through fitting of the calculated and measured oscillator strengths. J-O theory was used to evaluate the spontaneous emission probabilities, stimulated emission cross sections, branch ratios and energy level lifetimes of some useful transitions of Ho 3+ ions in NaY(WO 4 ) 2 crystals. The obtained three phenomenological J-O intensity parameters Ω 1 are Ω,-2.17x10 -19 , Ω 4 =1.58x10 -19 , Ω 6 =3.24x10 -20 for Pr 3+ ; Ω 2 =1.64x10 -19 , Ω 4 =7.43x10 -20 , Ω 6 =1.60x10 -20 for Ho 3+ .