EFFECT OF EXTERNAL ELECTRIC-FIELD ON R-LINE ABSORPTION-SPECTRA IN LINBO3-CR3+ CRYSTALS

The effect of an external electric field on the R absorption lines of LiNbO3 : Cr3+ crystals has been studied by a high-sensitivity differen tial technique at 77 K. Linear Stark effect has been observed in a fie ld directed along the trigonal crystal axis. No effect of the field wa s observed when directed perpendicular to this axis. These characteris tics of the Stark effect provide a convincing argument for the electri c dipole moments of Cr3+ centers being oriented along the trigonal C-3 axis of the crystal and indicate that the chromium centers in LiNbO3 have C-3 symmetry. (C) 1997 American Institute of Physics.