Heavy ion beam micromachining on LiNbO3

In this work 3D micromachining of x-cut lithium niobate crystals was performed using the high energy heavy ion microbeam (HIM) at the Tandar Laboratory, Buenos Aires. The samples were machined using ³⁵Cl beams at 70 MeV bombarding energy combined with wet etching with hydrofluoric acid solutions at room temperature. As the ion beam penetrates the sample, it induces lattice damage increasing dramatically the local etching rate of the material. This technique was applied to the fabrication of 3D waveguides with long control electrodes. The resulting structures indicate that well defined contours with nearly vertical sidewalls can be made. The results also show that with fluences of only 5 × 10¹² ions/cm², this technique is suitable for the fabrication of different shapes of LiNbO₃ control-waveguides that can be used in different optical devices and matched with the existing optical fibers.