Qinetiq Limited

Peter G R Smith

Graeme W Ross

Robert Eason

Ian E Barry

David Colin Hanna

David P Shepherd

Corin B E Gawith

A method of selectively etching a substrate () comprises applying etchant () at a surface of the substrate and illuminating an area of the surface with light from a light source (), whereby etching is at least partially inhibited in the illuminated area () of the substrate. Preferably LiNbO3 is patterned in HF KOH, or HF&#x2550;HNO3 solutions by selective illumination using UV laser light with 300 to 1000 mn wavelength, thereby allowing for interferometric or holographic structures to be formed.

Pattern formation method using light-induced suppression of etching

An optical waveguide with at least a guiding lamina ( ) of optical material bonded by direct interfacial bonding to a superstructure lamina ( ) of optical material, in which regions of the guiding lamina have modified optical properties so as to define a light guiding path along the guiding lamina. In a particular example, a periodically poled LiNbO planar waveguide is buried in LiTaO by direct interfacial bonding and precision polishing techniques and used in an optical frequency doubling system.

Optical waveguide and fabrication method

A method of etching structural depressions in a substrate comprises aligning the ferroelectric domains within the substrate to domain orientations selected from two or more possible domain orientations, whereby the rate at which substrate material is etched by an etchant varies with the domain orientation of the substrate material; and exposing the substrate to the etchant.

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Southampton, United Kingdom

Peter G R Smith