To meet the needs of high-density holographic data storage, researchers at Bell Laboratories have designed a new type photopolymer, a "two-chemistry" system, which yields high response, high photosensitivity media in millimeter-thick, optically flat formats. The media exhibit the some of the highest dynamic range of any holographic material and currently represent one of the few recording systems appropriate for high density digital holographic storage applications.

The media are fabricated from mixtures of two independently polymerizable yet compatible chemical systems. Recording disks are formed by an in-situ polymerization of one of the components to form the matrix or support of the medium. The other component, which is photosensitive, remains unreacted and dissolved in this matrix. Recording of holograms occurs through a spatial pattern of polymerization of the photosensitive species that mimics the optical interference pattern generated during holographic writing The concentration gradient that results from this patterned polymerization leads to diffusion of the unpolymerized species which creates a refractive index modulation that is determined by the difference between the refractive indices of the photosensitive component and the matrix. Our approach allows us flexibility in tailoring the media to the particular needs of high density holographic data storage.