Abstract: The medium comprises a bilayer stack constituted of an inorganic layer (30) and a semi-reflecting layer (32). The inorganic layer (30) can be deformed under the effect of light radiation (34) passed through the semi-reflecting layer, which lowers the reflection coefficient of the stack. Application to irreversible recording of information data, for example on discs.

Abstract: The medium comprises a bilayer stack constituted of an inorganic layer (30) and a semi-reflecting layer (32). The inorganic layer (30) can be deformed under the effect of light radiation (34) passed through the semi-reflecting layer, which lowers the reflection coefficient of the stack.

Abstract: An optical read/write device for an information medium which includes a transparent substrate having an approximately plane face carrying at least one pair of electrodes defining an airgap area whose size corresponds approximately to the size of the information item to be written or to be read. The pair of electrodes constitute a resonator for an incident electromagnetic wave having one component of its electric field parallel to the direction of alignment of the electrodes of the pair of electrodes. An optical source illuminates the electrodes with an optical beam, one component of the electric field of which is parallel to the direction of alignment of the pair of electrodes. Under these conditions, when excited by the beam F1, the electrodes will re-emit a beam which has a field concentration within the airgap. The re-emitted beam makes it possible to read/write information on an information medium placed near the electrodes.