Fig. 1. XRD patterns of NaLu（WO₄）₂∶x mol% Tm³⁺ （x=0.5~50.0）， and NaLu（WO₄）₂∶1.0 mol% Tm³⁺， y mol% Yb³⁺ （y=0.5~20.0） samples and the standard data reported in JCPDS card No. 27-0729

Fig. 2. Excitation spectra for NaLu（WO₄）₂：x mol% Tm³⁺ （x=0.5~50.0） samples by monitoring 796 nm emission

Fig. 3. Emission spectra of NaLu（WO₄）₂：x mol% Tm³⁺ （x=~50.0） phosphors under 279 nm excitation

Fig. 4. 300~900 nm emission spectra， and 700~1 200 nm emission spectra for NaLu（WO₄）₂∶1 mol% Tm³⁺/y mol% Yb³⁺ （y=0~20.0） phosphors under 279 nm excitation

Fig. 5. Fluorescence decays of ¹D₂， ¹G₄， ³F_{2， 3}， and ³H₄ levels of Tm³⁺ in NaLu（WO₄）₂∶1.0 mol% Tm³⁺/y mol% Yb³⁺（y=0~20.0） phosphors

Fig. 6. Energy level diagram and quantum cutting routes of Tm³⁺ and Yb³⁺ co-doped NaLu（WO₄）₂ phosphors

Fig. 7. Dependences of energy transfer ET1 efficiency， energy transfer ET2 efficiency， quantum efficiency of ²F_5/2 level of Yb³⁺ and quantum cutting efficiency on Yb³⁺ concentration

Fig. 8. Fluorescence decays for ²F_5/2→²F_7/2 transition of Yb³⁺ in NaLu（WO₄）₂∶1 mol% Tm³⁺/y mol%Yb³⁺（y=0.5，1.0，5.0，10.0，20.0）phosphors