Editorial: Math. Log. Quart. 1/2008

A method is provided for pattern masking objects preparatory to subsequent working of the objects. The invention also includes those objects prepared in accordance with the method. The method is especially suited to the pattern-masking of relatively large and/or complexly shaped optical elements preparatory to the production of diffraction gratings thereat for use with laser radiation. The object to be worked, such as a mirror, is coated with a semiconductive masking material. Electrolytic etchant is placed on the masking material. Electromagnetic radiation of suitable wavelength and patterned in accordance with the desired pattern of the mask is projected through the etchant and onto the masking material. The radiation effects photoelectrochemical etching of the semiconductive masking material in the desired pattern to a desired depth. An etch-stop layer may be interposed between the object and the masking material to limit the etching action. The desired working of the substrate object, as for instance the formation of diffraction gratings thereat, may then be achieved, as by ion milling, deposition, or the like. The mask, and etch stop, if any, may finally be totally removed by suitable etch baths.