Enhanced electro-optic effect in potassium lithium tantalate niobate at the paraelectric phase near Tc

Abstract

The electrooptic effect in potassium lithium tantalate niobate (KLTN) at the paraelectric phase in close proximity to Tc was investigated, and was found to be exceptionally large. At Tc+3°C, the electrically induced change in the refractive index was measured to be ≈0.014 while high optical quality was maintained. It is also shown that at the paraelectric phase, close to Tc, the electrooptic behavior deviates from being directly proportional to the square of the electrically induced polarization P2. This is attributed to the influence of dipolar clusters that are formed upon cool-down towards Tc. Taking this influence into account, it was shown that the electrooptic effect close to Tc remains quadratic, enabling the inhibition of photorefractive optical damage by employing a bi-polar driving voltage.