Study On The Spectrum Character Of Nd～(3+) And Yb～(3+) Doped KGd(WO₄)₂ Laser Crystals

KGd(WO₄)₂ laser crystal is a new laser substance material develop upon CaWO₄ crystal. Regardless operate in freedom, under control of Q value or LD pumping, it all show high efficiency. It has good mechanism, optics behave,can be high-doped and has potential in non-linearity and Raman scatter area .but it hard to grow and a bit low heat exchange capability which can slowly be solved by the improve of grow technique and pumping at the very wavelength .So the crystal supposes to be premising substance in the field of medical treatment, communication, electron, remote sensing , industry and so on . Now It get many attention and become a research hotspot.The paper research the spectrum character of two doped ions, Nd³⁺a nd Yb³⁺,in KGW crystals.First, the absorption and fluorescent spectra at room temperature were measured. According to Judd-Ofelt theory and Reciprocity method, we calculate they basic spectrum parameter in Nd³⁺doped and Yb³⁺ doped KGW,such as the oscillator strength, spontaneous radiative rate, branching ratio, integrated emission cross-section and laser emission cross-section and so on. The possibility and characteristic for Nd³⁺andYb³⁺doped KGW crystal as laser material are discussed.Because KGW is double- axis crystal, has different character in each side. The paper emphasize on the influence of this identity to its spectrum behave. On one hand, take it suit for LD puming into account, the infection of polar direction and incidence direction of pumping light to crystal fluorescent spectra is measured ,which may be theory basis for design LD pumping solid laser. On the other hand, The Raman spectrum with different direction into and output was measured and the Raman vibronic mode of KGW crystal is given in theory,which may be useful in design Raman laser.The doped concentration is one important parameter to laser output character and efficiency. When it increases, the number of work ions become more and the output light intension become stronger. But if it increases by some value, the space between ions become closer and they act with each other which make the lower efficiency. So the ascertain of best dope concentration is important. We calculate the best concentration depend on experiment data and calculate result in theory. The value is 4.6at%.Finally, we can get the result that Nd³⁺andYb³⁺doped KGW crystal is a promising laser...