STARK-EFFECT ON CR3+ SPECTRA IN LINBO3

The electric field effect on the absorption spectra of Cr3+ impurity c enters in LiNbO3 has been investigated at 77 K using a sensitive modul ation method. A linear Stark effect on B- and R- absorption lines of C r3+ was observed for a field applied along the trigonal crystal axis Z , and no effect was detected when field was normal to Z. Such properti es establish that the permanent dipole moments of the observed Cr3+ ce nters are oriented alone the trigonal crystal axis proving their C-3 p oint symmetry. The quantitative characteristics of the held effect are obtained. The marked peculiarity of the Stark effect in LiNbO3:Cr3+ i s the opposite sign of the electric field shift of B-1 and B-2 lines.