An optical device has varying index of refraction

This invention relates to an optical device comprising an ion conductor composed of a material transparent to light containing movable ions and at least one pair of electrodes capable of absorbing and desorbing ions in ionic contact with the ion conductor. The refractive index in at least one zone of the ion conductor is liable to vary under the effect of the voltage applied between the electrodes. The electrodes contain an electrochemically active material selected from an active carbon, a conductive polymer and an insertion material suitable for inserting ions in its structure.