Photo-tautomer of Br-porphyrin: a new frequency-selective material for ultrafast time-space holographic storage

We study spectral hole burning in the unstable tautomer form of free-base B r-tetraethylporphyrin in poly(vinyl butyral) film, which is created by phot o-transformation of the stable tautomer form at low temperature. We report a Debye-Waller factor alpha = 0.7 at 4 K, burning quantum efficiency phi si milar to 10(-3) and thermal stability up to 115 K for this system. We obser ve for the first time that narrow-band illumination in the educt band leads to the formation of vibronic holes in the photoproduct band. Because the o scillator strength of the unstable form is at least one order of magnitude larger than that of the stable form, this new material is well suited for r ecording ultrafast time-and-space-domain holograms. Spectral hole burning w ith femtosecond pulses was achieved. (C) 2000 Elsevier Science B.V. All rig hts reserved.