Electron-lattice coupling in congruent co-doped LiNbO₃:Cr³⁺:ZnO crystal

Abstract

The importance of the role of the ion lattice coupling in determining the energy levels of Cr³⁺ ions in congruent LiNbO₃ crystals doped with 2.9% of ZnO is demonstrated in this paper. The Racah parameters: <i>B</i> 533 cm 1, <i>C</i> 3244 cm⁻¹ and the crystal-field intensity <i>Dq</i> = 1527 cm⁻¹ were determined and the Tanabe-Sugano diagram was constructed. The characteristics of the absorption and the emission spectra of Cr³⁺ ions in these crystals can be explained in terms of the configurational-coordinate diagram in the harmonic approximation, with good agreement obtained. The Huang Rhys parameter S 6.86 and the lattice phonon energy <i>hw</i>= 343 cm⁻¹ are also reported in this work