Abstract: An optical data storage system and method that utilizes the frequency dimension to increase the storage capacity significantly. The system includes a storage material, for example, in the form of a block, adapted to undergo a photo induced reaction upon exposure to light and which exhibits inhomogeneous absorption line broadening. Data bits are stored by selective photo induced reactions induced by a narrow band laser at specific frequencies within the broad inhomogeneous line. The lifetime of these photo induced data bits is of the order of years so as to provide a non-volatile storage system. In a preferred embodiment, a material is selected so that the photo induced reaction can be made reversible thereby permitting, when desired, the erasing of the data bits.