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 (+z-face) of a thin Fe-doped LiNbO3 sample, whose front face (-z-face) is in contact with the etchant solution. At power densities of > 100 W cm(-2), 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. (C) 1999 Elsevier Science B.V. All rights reserved.