Holographic double-microgratings were written one-off in Ag2O-doped silicate glass by a single femtosecond laser pulse with the aid of heat treatment for half an hour at 500degreesC. Transmission electron and optical microscopic observations show that the double-micrograting was formed from Ag nanoparticles precipitation in the glass. Also, the first-order diffraction efficiency of the double-micrograting was measured to be similar to4.9%. The present technique is applicable not only to fast encoding multiple holographic microgratings in all non-photosensitive transparent dielectric material but also to fabricating nanostructured devices such as quantum wire arrays, photonic crystals and optical switches. (C) 2003 Elsevier B.V. All rights reserved.