Abstract: A glass flake comprising a flake of glass having formed on its surface a metal covering layer on which is formed a dense protective covering layer of a metal oxide. The glass flake is produced by maintaining a flake of glass in an alkaline solution containing metal alkoxide, water and an alcohol, followed by the separation and firing thereof.

Abstract: An electro-optic material has at least a pair of confronting elongated electrodes formed on at least one surface thereof. Preferably, each of the electrodes has a plurality of elongated, spaced parallel fingers which interleave with each other (sometimes called "interdigital electrodes"). When a high-frequency signal is applied across the electrodes, the refractive index changes in a linear or nonlinear manner within a layer of the body of the electro-optic material which is near the electrodes. The amount of the index change may be varied by a proper selection of materials, signals and geometrical material configuration.