Abstract
We investigated the composition dependence of photorefractivity, beam distortion, Raman lines, and birefringence in reduced pure lithium niobate. When lithium content reaches the value of 49.4 mol %, abrupt changes were observed for all these optical properties except birefringence. We suggest that such a behavior may be due to a change in the phonon spectrum occurring around the critical composition. (C) 2011 American Institute of Physics. [doi:10.1063/1.3580764]