Nano-sized domain inversion characteristics in LiNbO3 group single crystals using SNDM

This is, we believe, the first report on nano-sized domain inversion characteristics in congruent LiNbO3 (CLN), MgO doped LiNbO3 (MgO:LN) and stoichiometric LiNbO3 (SLN) single crystals brought out using scanning dielectric nonlinear microscopy method. Thin crystal plates for forming nano-sized domain inversions were prepared by chemical mechanical polishing and an ion beam etching process. The small domain dot of 13 nm in radius was formed in CLN. However, the domain dots in CLN tended to disappear. The smallest domain dot of 6.1 nm in radius was obtained in MgO:LN. The domain dot array was also successfully formed at a density of 558 Gbit/in.2. In case of higher application voltage, a unique result was obtained in MgO:LN showing that the sizes of domain inversions were almost constant against the voltage pulse width. It is not easy to form domain dot array in SLN since the sidewise growth speed in SLN is very fast.