In ZnWO4 the Cr3+ ion is substituted for the relatively large Zn2+ site. Therefore, the crystal field strength at the Cr3+ site is rather low, and an extreme red shift of the absorption and emission bands occurs. No R lines are observed; i.e., all emission arises from the broadband 4T2-4A2 transition. In addition the crystal field splits the 4T2 level because of its low symmetry (symmetry 2, level separation 1.000 cm−1). This yields a further red shift of the emission band with maximum intensity near 1-µm wavelength.
© 1984 Optical Society of AmericaPDF Article