Patent ID: 8475975

Claim:
A method for recording holographic data in an optical data storage medium, said method comprising: (i) providing an optical data storage medium comprising: (a) a thermoplastic polymer matrix, (b) a latent acid generator, (c) a sequential two-photon non-linear sensitizer, and (d) a reactant comprising a latent chromophore; (ii) irradiating a volume element of the optical data storage medium with an interference pattern to cause sequential two-photon absorption by the non-linear sensitizer; (iii) an upper triplet energy transfer from the non-linear sensitizer to the latent acid generator, thereby generating an acid, said interference pattern comprising an incident radiation having a wavelength and an intensity sufficient to cause the upper triplet energy transfer, wherein the latent acid generator is substantially non-responsive to said incident radiation; (iv) reacting at least one latent chromophore with the acid generated to form at least one chromophore, thereby causing a refractive index change within the volume element; and (v) producing within the irradiated volume element refractive index variations corresponding to the interference pattern, thereby producing an optically readable datum.