Thermally assisted growth of bulk domains created by femtosecond laser in magnesium doped lithium niobate

The domain growth to the polar surfaces from the tracks created by focused NIR femtosecond pulses in the bulk of MgO-doped lithium niobate plate has been studied. The tracks have been imaged by optical and Cherenkov-type second harmonic generation microscopy. The domain appearance at the irradiated surface has been attributed to domain nucleation and growth under the action of the pyroelectric field arising during cooling after heating by pulse irradiation. The pyroelectric field produced during the sample cooling has stimulated the domain growth to both polar surfaces. The obtained knowledge can be used for development of the domain engineering.