UV laser induced ferroelectric domain inversion in lithium niobate single crystals

UV radiation in the spectral region beyond ~ 320 nm is strongly absorbed by lithium niobate single crystals. The strong absorption and the consequent localized heating of the crystal triggers physical processes which can affect the state of the material not only by changing the refractive index, as shown in the past, but also by changing its ferroelectric disposition. UV laser irradiation of the polar surfaces in particular can induce or inhibit the inversion of ferroelectric domains. A summary of these UV light induced effects and their utility in the microstructuring of this very important optical ferroelectric crystal will be presented here.