  Ferroelectric domain inversion and its effect on the stability of lithium
niobate thin films on insulator (LNOI) are experimentally characterized. Two
sets of specimens with different thicknesses varying from submicron to microns
are selected. For micron thick samples (~28 um), domain structures are achieved
by pulsed electric field poling with electrodes patterned via photolithography.
No domain structure deterioration has been observed for a month as inspected
using polarizing optical microscopy and etching. As for submicron (540 nm)
films, large-area domain inversion is realized by scanning a biased conductive
tip in a piezoelectric force microscope. A graphic processing method is taken
to evaluate the domain retention. A domain life time of 25.0 h is obtained and
possible mechanisms are discussed. Our study gives a direct reference for
domain structure-related applications of LNOI, including guiding wave nonlinear
frequency conversion, nonlinear wavefront tailoring, electro-optic modulation,
and piezoelectric devices.
