HOLOGRAPHIC RECORDING AND ALL-OPTICAL MODULATION IN PHOTOCHROMIC POLYMERS

Polymers doped with photochromic spirooxazine and spiropyran dyes have been investigated for real-time holographic recording. The temporal holographic response was found to depend strongly on optical recording configurations and on the recording beam intensities. The exposure sensitivities that were required for maximal diffraction efficiency were 250 mJ/cm2 for the polymers doped with spirooxazine and 650 mJ/cm2 for those doped with spiropyran. All-optical modulation of the holographic gratings with 2000 lines/mm is possible by modulation of a separate excitation beam of incoherent UV radiation. The modulated gratings can be stored for relatively long times or erased immediately.