Ultraviolet laser-induced submicron spatially resolved super-hydrophilicity on single crystal lithium niobate surfaces

Abstract

Lithium niobate crystal surfaces become super-hydrophilic after ultraviolet laser irradiation. The crystal surface hydrophilicity, which was assessed by the contact angle of a sessile drop of de-ionised water, was found to undergo a transition from mildly hydrophobic (contact angle, theta[E] < 50°) to a super-hydrophilic state (theta[E] < 5° ). Patterning of the hydrophilicity at the micron and sub-micron range has been achieved by spatially modulating the illuminating laser beam