Abstract: The invention provides a method for the production of a photonic device comprising providing a substrate, forming in the substrate substantially straight pores, lining or filling the pores with a material having voltage-dependent index of refraction, and removing part but not all of the substrate materials so that an array remains of tubes or rods of material having. voltage-dependent index of refraction. In a variant of the method the deposited material is piezoelectric and the substrate is completely removed, resulting in piezoelectric tubes or rods of small diameter, generally below 10 ?m.

Abstract: According to the invention we provide a process for filling or lining the pores of a porous silicon, silica or alumina substrate with a material which exhibits voltage-dependent index of refraction n comprising providing precursors for the deposited material as a precursor solution, forming a fine mist of droplets of precursor solution and applying the droplets to the porous substrate. The invention provides for the first time porous silicon, silica and alumina substrates having fill fraction at least 60%. Fill fractions of close to 100% can be achieved. When provided with top and bottom electrodes, filled porous silicon, silica and alumina wafers can be used as voltage-dependent photonic devices. The same process can be used for lining trenches in the surface of a silicon substrate, for instance for use in production of microelectronic devices such as random access memories.