Absorption spectrum analysis of Nd∶KY(WO₄)₂ and Nd∶KG(WO₄)₂ crystals

Nd∶KY(WO4)2 and Nd∶KG(WO4)2 crystals are proved to be good laser crystals through the analysis of their absorption spectrum at room temperature. According to the absorption spectrum and data derived from Judd-Ofelt theory as well as measured absorption and data obtained from the test, VC++ program was used to calculate the intensity of spectral line, oscillator strength and absorption cross-section of the crystals. Then the values of three crystalfield adjusting parameters Ωλ(λ=2, 4, 6) of Nd3+ ion were obtained by fitting calculation. The spontaneous transition probability, energy level lifetime, fluorescence branch ratio and integrated emission cross-section were calculated theoretically. The calculated fluorescence branch ratio β indicates that the fluorescence branch ratios of both Nd∶KY(WO4)2(β1060nm=0.4380) and Nd∶KG(WO4)2(β1060nm=0.4618) crystals are large. At last, X=Ω4/Ω6 of Nd∶KY(WO4)2 and Nd∶KG(WO4)2 crystals were calculated and compared with those of other laser crystals. It is concluded that Nd∶KY(WO4)2and Nd∶KG(WO4)2crystals can produce 1060nm laser.