Method for thermally erasing information stored in an aluminum oxide data storage medium
View Patent ↗The present invention provides methods and apparatuses for writing information to, reading information from, and erasing information on a luminescent data storage medium comprising Al 2 O 3 . The method includes writing and erasing of the information using photoionization via sequential two-photon absorption and non-destructive reading the information using fluorescent detection. The apparatuses for writing and reading the information incorporate confocal detection and spherical aberration correction for multilayer volumetric fluorescent data storage. The methods also allow multilevel recording and readout of information for increased storage capacity.
1. A method of erasing information stored on a data storage medium comprising the steps of:
(a) providing a luminescent data storage medium comprising Al 2 O 3 , said luminescent data storage medium having said information stored thereon; and
(b) thermal annealing said luminescent data storage medium at a temperature of about 600 to 700° C. to thereby erase said information on said luminescent data storage medium.
2. The method of claim 1 , wherein step (b) comprises annealing said data storage medium at a temperature of about 650° C.
3. The method of claim 1 , further comprising the step of:
cooling said luminescent data storage medium to room temperature.
4. The method of claim 1 , wherein at least part of the said luminescent data storage medium is a single crystal Al 2 O 3 material.
5. The method of claim 1 , wherein said luminescent data storage medium comprises:
a base material comprising Al 2 O 3 ;
a first dopant comprising magnesium; and
a second dopant comprising carbon, wherein said luminescent data storage medium includes a plurality of at least one type of oxygen vacancy defect.
6. The method of claim 5 , wherein said luminescent data storage medium includes color centers having 335 and 630 nm optical absorption bands and a 750 nm fluorescent emission band prior to step (b), and wherein said color centers having 335 and 630 optical absorption bands are converted by step (b) into color centers having a 435 nm optical absorption band and a fluorescent emission band at 520 nm.
7. The method of claim 5 , wherein said Al 2 O 3 :C,Mg crystal has a green coloration and has original concentration of F 2 2+ (2Mg)-centers prior to said information being stored on said luminescent data storage medium, and wherein step (b) comprises restoring said green coloration and said original concentration of F 2 2+ (2Mg)-centers.
8. An apparatus for erasing information stored on a data storage medium comprising:
a luminescent data storage medium comprising Al 2 O 3 , said luminescent data storage medium having said information stored thereon; and
annealing means for thermal annealing said luminescent data storage medium at a temperature of about 600 to 700° C. to thereby erase said information on said luminescent data storage medium.
9. The apparatus of claim 8 , further comprising cooling means for cooling said thermally annealed data storage medium to room temperature.
10. The apparatus of claim 8 , wherein at least part of the said luminescent data storage medium is a single crystal Al 2 O 3 material.
11. The apparatus of claim 8 , wherein said luminescent data storage medium comprises:
a base material comprising Al 2 O 3 ;
a first dopant comprising magnesium; and
a second dopant comprising carbon, wherein said luminescent data storage medium includes a plurality of at least one type of oxygen vacancy defect.
12. The apparatus of claim 11 , wherein said luminescent data storage medium includes color centers having 335 and 630 nm optical absorption bands and a 750 nm fluorescent emission band while said information is stored on said luminescent data storage medium, and wherein said color centers having 335 and 630 optical absorption bands are converted into color centers having a 435 nm optical absorption band and a fluorescent emission band at 520 nm by annealing said luminescent data storage medium at a temperature of about 650° C.
13. The apparatus of claim 12 , wherein said Al 2 O 3 :C,Mg crystal has a green coloration and has original concentration of F 2 2+ (2Mg)-centers prior to said information being stored on said luminescent data storage medium, and wherein said annealing means is capable of restoring said green coloration and said original concentration of F 2 2+ (2Mg)-centers.