A new gated system for two-photon holographic recording in the near infrared

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Abstract
A new two‐photon method for recording holograms is presented. It is based on the fact that a first photon produces singlet oxygen by a photosensitization process; this species oxidizes a specific trap to produce a carbonyl compound. This latter is used as a conventional polymerization initiator and produces active species after the absorption of a second photon. The feasibility of this general process is demonstrated by using Methylene Blue (photosensitizer), diphenylisobenzofuranne (singlet oxygen trap), and a mixture of acrylamides (polymerizable compound). Finally, diffraction efficiencies higher than 2% are easily achieved with such systems. The influence of different experimental parameters was studied with a view to extending the sensitivity of the system to the infrared.