Interference Lithography Patterned Nanogratings in LiNbO3 Fabricated by Dry Etching

Abstract

Channel waveguides have been fabricated in x-cut lithium niobate (LiNbO3) by proton exchange (PE) method and optically measured. The thickness and the optical constants of the thin PE layer were characterized using a prism coupling technique. The PE area was plasma etched and a 2.775-μm total etching depth was achieved. The measured average etching rate is 92.5 nm/min. One-and two-dimensional dense arrays of LiNbO3 nanostructures have also been fabricated by using interference lithography (IL) and inductively coupled plasma reactive ion etching (ICP-RIE) techniques.Intorduction