Near-infrared holography by two-photon photochemistry

The applicability of the technique of two-photon four-level photochemistry for the production of near-IR holograms is critically evaluated. Although the current best system (biacetyl in a polycyanoacrylate matrix) has low recording sensitivity, several applications of the material have been demonstrated. Hologram efficiencies of up to 70% recorded at 752 nm are shown. Recording of extended holographic images and production of holographic optical elements are demonstrated. Finally, we have recorded holograms directly with GaAlAs diode lasers.