An optical data storage system that utilizes the frequency dimension to increase the storage capacity. The storage system has a storage material which contains a guest material such as cinnoline, which is dissolved in a host material such as naphthalene. This storage material system exhibits an inhomogeneous absorption line broadening and undergoes a photochemical reaction upon exposure to light.
A frequency selective optical data computer memory apparatus and method, which stores and accesses time modulated data in discrete spatial locations of an optically absorbing material providing a temporary, permanent and erasable, or permanent and nonerasable data storage.
The storage medium for an optical data storage system is a contiguous laminate formed by a plurality of layers of photochemical hole burning material, such layers individually exhibiting inhomogeneous absorption spectrum characteristics spanning different, successive wavelength ranges. This arrangement greatly expands the cumulative or overall absorption band of the storage medium available for laser hole burning to implement data bit writing, and thus increases the storage density at each memory site.
Data storage methods and apparatus are disclosed that utilize a swept-carrier optical approach with an inhomogeneously broadened absorber material having multiple special storage cells. Data are encoded on a data pulse by appropriately modulating the data pulse. Data storage in a storage cell is effected by exposing the cell to the data pulse and a reference pulse cotemporal with the data pulse. Both the data and reference pulses are frequency-chirped across the inhomogeneously broadened bandwidth of the absorber material, the data pulse being chirped at a frequency that is offset relative to the reference pulse. Data retrieval from the storage cell is performed by exposing the cell to a read pulse which causes the cell to produce a signal pulse comprising the encoded data. The read pulse can have a temporal profile that produces a signal pulse shaped either similarly to the data pulse or as a mirror image of the data pulse.
In an optical recording medium, 4,8-diamino-2-(4-hexyloxyphenyl)-1,5-dihydroxyanthraquinone is used as guest molecules, for an optical recording layer, and a compound expressed by a general formula (1): ##STR1## (where R.sub.1 denotes H or CH.sub.3, R.sub.2 denotes C.sub.2 H.sub.4, C.sub.3 H.sub.6 or C.sub.4 H.sub.8, and n denotes an integer) is used for the host molecules. Since holes are caused in the wavelength region of the semiconductor laser, optical recording can be performed efficiently by using a semiconductor laser.
An optical recording material (21a) or a photochemical hole burning reaction. That is to say, informations are recorded in the recording material formed of a recording member in which molecules (D.sub.1) to (D.sub.3) having a property of changing characteristics of an optical absorption spectrum before and after the absorption of light by absorbing a light within an inherent wavelength range of the optical absorption spectrum are linked with at least one macromolecular chain (P). The optical recording material can be used in memories in the computer system and the like.
