Non-volatile data storage medium and system
AssigneeEcole Polytechnique Federale De Lausanne (Epfl)
InventorsRuben Ricca, Yves Bellouard, Martin Vetterli
Life of this patent
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Abstract
A data storage medium (2) comprising a stacked plurality of layers (9), each layer composed of a layer material selected from a group comprising at least two different dielectric materials, adjacent layers being formed of different materials, and at least one of the layers, that is not a top layer, constituting an information layer (9i) configured to be modified locally by energy from an electromagnetic beam (7) having a specific beam wavelength and a propagation direction (Z) transverse to the layers. The stacked plurality of layers include an aperiodic layer arrangement including at least three stacked adjacent layers having different thicknesses with respect to each other.
Claims28
A data storage medium, comprising:
- a stacked plurality of layers, each layer composed of a layer material selected from a group comprising at least two different dielectric materials, adjacent layers being formed of different materials, at least one of the layers, that is not a top layer, constituting an information layer configured to be modified locally by energy from an electromagnetic beam having a specific beam wavelength and a propagation direction (Z) transverse to the layers, and at least one of the layers constituting a spacer layer configured not to be modified locally by energy from said electromagnetic beam, wherein the stacked plurality of layers include an aperiodic layer arrangement including at least three stacked adjacent spacer layers having different thicknesses with respect to each other, said information layer downstream and adjacent the aperiodic stacked layer arrangement, wherein the information layer has a thickness t in the propagation direction Z, of equal or less than λ/4η:
- t≤λ/4η where λ is said specific beam wavelength and η is the refractive index of the material, the thickness ti of the information layer being preferably in a range of λ/20η<ti<λ/4η, more preferably λ/10η<ti<5η.
A data storage medium, comprising:
- a stacked plurality of layers, each layer composed of a layer material selected from a group comprising at least two different dielectric materials, adjacent layers being formed of different materials, at least one of the layers, that is not a top layer, constituting an information layer configured to be modified locally by energy from an electromagnetic beam having a specific beam wavelength and a propagation direction (Z) transverse to the layers, and at least one of the layers constituting a spacer layer configured not to be modified locally by energy from said electromagnetic beam, wherein the stacked plurality of layers include an aperiodic layer arrangement including at least three stacked adjacent spacer layers having different thicknesses with respect to each other, said information layer downstream and adjacent the aperiodic stacked layer arrangement, wherein the information layer has a thickness of less than 20% (ti<0.2Lr), preferably less than 15% (ti<0.15Lr), of a Rayleigh length Lr of the electromagnetic beam in the data storage medium.
Dependencies are inferred from the claim text.