Patent ID: 7507504

Claim:
A method of optically recording information in a storage medium comprised of a polymer material doped with a plurality of azobenzene molecules, each of the plurality of azobenzene molecules possessing molecular reorientation properties and being isomerizable from a trans isomer to a cis isomer upon irradiation with light having a blue wavelength, and being isomerizable from the cis isomer to the trans isomer upon one of thermal relaxation and irradiation with light having a red wavelength, the method comprising: partially reorienting the plurality of azobenzene molecules by irradiating the storage medium with a first coherent light source that irradiates the storage medium with light having the red wavelength, and light from a second light source that irradiates the storage medium with light having the blue wavelength, wherein the light from the second light source has a p-polarization and is uniform, while the light from the first coherent light source has an s-polarization and forms a pattern that represents the information being recorded, the pattern providing bright fringes in a first plurality of locations in the storage medium and providing dark fringes in a second plurality of locations in the storage medium, wherein, in the first plurality of locations and the second plurality of locations, the light from the second light source interacts with trans isomers that are not oriented perpendicularly to the p-polarization by isomerizing said trans isomers to cis isomers, and wherein, in the first plurality of locations, the light from the first light source interacts with cis isomers by isomerizing said cis isomers to trans isomers; and generating a nonvolatile orientation grating at a temperature below a glass transition temperature of the polymer material by removing the light from the first coherent light source and the second light source for a relaxation period of time selected to be sufficiently long that cis isomers in the second set of locations relax to trans isomers having random orientations, while substantially all isomers located in the first set of locations are trans isomers having an orientation essentially perpendicular to the p-polarization.