Continuous wave ultraviolet radiation induced frustration of etching in lithium niobate single crystals

Illumination of the −z face of congruent lithium niobate single crystals with continuous wave (c.w.) ultraviolet (UV) laser radiation modifies the response of the surface to subsequent acid etching. A frequency doubled Ar+ laser (λ=244 nm) was used to illuminate the −z crystal face making it resistive to HF etching and thus transforming the illuminated tracks into ridge structures. This process enables the fabrication of relief patterns in a photolithographic manner. Spatially resolved Raman spectroscopy indicates preservation of the good crystal quality after irradiation.