Fabrication of Very-Deep Nanometer-Size Domain Inversion in LiNbO3 by Circular Form FCE

Very-deep nanometer-size domain inversions in lithium niobate (LiNbO₃) substrate have been realized using circular form full cover electrode (CF-FCE) for the first time. From the calculated results, circular form electrode is better than that of rectangular type for fine domain inversion patterns. Domain inversion was performed by applying high voltage to circular form FCE. Using the CF-FCE, the authors successfully fabricated 2 mum periodic domain inversion in a 500-mum-thick congruent LiNbO₃ (C-LN) crystal. It is also shown that smaller domain inversion width in the nanometer regime with high aspect ratio is possible using this technique. The authors obtained an aspect ratio as high as 870 for a domain inversion width of 575 nm