Absorption spectra and Raman spectra of Dy:NaGd(WO<sub>4</sub>)<sub>2</sub>(Dy:NGW) and Dy:NaLa(WO<sub>4</sub>)<sub>2</sub>(Dy:NLW) crystal at room
temperature are investigated. Although the structure of them are similar, there is a bit discrepancy between Dy:NGW and
Dy:NLW of the set of spectra corresponding to the radius of Nd<sup>3+</sup>, La<sup>3+</sup> and Gd<sup>3+</sup>. According to J-O theory, the oscillator
strength and intensity parameter are calculated and discussed. Due to the disordered structure of the host, the absorption
bands are strongly inhomogeneously broadened. The absorption broad bandwidth reduces the requirements on laser
diodes for zero-phonon-line (ZL) pumping with respect to the spectral bandwidth and wavelength stability for different
power levels. The same differences happen in the Raman spectra. It is beyond doubt that Dy<sup>3+</sup>-doped compounds,
including the low energy-phonon crystals will be one kind of very promising material in the laser application.