Light-induced frustration of etching in Fe-doped LiNbO3

We report the results of light-induced frustration of the normal etching behaviour observed when LiNbO3 is immersed in a solution of HF and HNO3 acids. Light of wavelength 488 nm, from an air-cooled 100 mW Ar ion laser, is incident on the rear surface qz-face.of a thin Fe-doped LiNbO3 sample, whose front face yz-face.is in contact with the etchant solution. At power densities of )100 W cmy2, etching is suppressed through light-induced charge migration. Below this power density, partial suppression occurs, leading to submicron scale features, whose orientation follows the crystal symmetry. q1999 Elsevier Science B.V. All rights reserved.