Surface-relief diffraction gratings based on selective etching of periodically poled lithium niobate

Abstract

This work reports the use of selective etching in a periodically poled crystal of LiNbO3 (MgO):Yb3+ to engineer a surface-relief diffraction grating. A 35.1%–64.9% fill factor (domain duty cycle) grating with a 6.86 μm domain period is presented. The diffraction grating created provides a simple tool for accurate characterization of domain size and structure homogeneity. Following a similar process, arbitrary surface-relief two-level binary diffractive optical elements can be patterned in domain-engineered lithium niobate crystals.