Abstract: A recordable medium includes an inscription layer and a contrast enhancing layer. The inscription layer has at least two sub-layers that combine upon application of a write power, the inscription layer having a reflectivity R1 before application of the write power and a reflectivity R2 after application of the write power. The contrast enhancing layer does not combine with the sub-layers of the inscription layer upon application of the write power. The contrast enhancing layer and the inscription layer together have a reflectivity R3 before application of the write power and a reflectivity R4 after application of the write power, and |R4?R3|>|R2?R1|.

Abstract: A recordable medium includes a recordable structure including a first layer having a reflectivity R1 and a transmissivity T1, a second layer having a transmissivity T2, and a third layer having a reflectivity R3. The second layer is disposed between the first and third layers and has a thickness that is less than a Debye length determined based on a charge density of the second layer. The recordable structure has an overall reflectivity Rsum that is greater than R1+T12*T22*R2.

Abstract: A recordable medium includes a recordable structure having a first layer and a second layer in which the first and second layers do not completely overlap, and the first and second layers combine upon application of a write power to cause a change in an optical property of the recordable structure with respect to a read beam. In some examples, at least one of the first and second layers includes discontinuous regions. In some examples, at least one of the first and second layers includes a contiguous region having a shape that forms holes. In some examples, the Debye length of at least one of the first and second layers is less than 5 nm, the Debye length being determined based on a charge carrier density in the layer.

Abstract: An optical recordable medium at least comprises a recording layer formed on a transparent substrate. The recording layer is sequentially formed on a first transparent layer, a semi-reflective layer, a dielectric layer, a reflective layer and a material layer. When a modulated writing beam irradiates the recording layer and data is written in a recorded area, the first transparent layer and the semi-reflective layer react to form a second semi-reflective layer. When a reading light irradiates the recorded area, the light wave phase is shifted and the recorded area becomes anti-reflective.