Photographic-image storage in ion-implanted PLZT ceramics

Photographic images can be stored in transparent lead lanthanum zirconate titanate (PLZT) ceramics using near-UV light with photon energies near the band gap energy of 3.42 eV. Coimplanting inert ions, e.g., Ar, Ne, and He, into the surface exposed to image light can increase near-UV photosensitivity by a factor of almost 10,000 with no degradation of image quality, so that the exposure energy threshold is reduced from approx. 100 micron J/sq cm to approx. 10 micron J sq cm. Coimplanting chemically active and inert ions, e.g., Al or Cr and Ne, can result in similiar improvement of the extrinsic (visible light) photosensitivity and in an essentially flat photoresponse from about 400 to 600 nm. In addition, thermal diffusion of Al followed by Ne implantation yield photosensitivity increases in the near-UV comparable to the best results obtained to date with ion implantation.