Fabrication of sub-micron period surface structures in LiNbO₃

Sub-micron period reversed domain patterns are fabricated in congruent LiNbO3 by using electric field overpoling. Slight wet etching of the domain engineered samples in HF solution generates surface relief structures faithfully reproducing the resist pattern geometries generated by holographic lithography. Moiré holographic lithography is also used to fabricate more complicated resist templates to be transferred onto the LiNbO3 substrates as surface structures. A wide variety of structures is presented and discussed. The preliminary results show the possibility to use the fabricated structures for the realization of photonic crystal devices such as Bragg gratings, micro-ring resonators, etc. for telecom applications.