Nonlinear optical constants of ionic conductors : a study based on the Sheik-Bahae equation

Guided by the prediction of the bond fluctuation model of superionic conductors, the relation between the nonlinear optical constants and the ion transport properties in ionic conductors has been studied. Since the measured values of nonlinear optical constants in ionic conductors are very limited, they have been evaluated through the Sheik-Bahae equation. Using such values, it is shown that the activation energy of ion transport and the superionic transition temperature decrease with the increase of the nonlinear refractive index. It is also pointed out that the band gap energy and the linear refractive index in superionic conductors are relatively weakly correlated when compared with non-superionic materials. The development of a new field of study that could be called photoionics is suggested