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 Br-tetraethylporphyrin in poly(vinyl butyral) film, which is created by photo-transformation of the stable tautomer form at low temperature.We report a Debye–Waller factor α=0.7 at 4 K, burning quantum efficiency ϕ∼10 −3 and thermal stability up to 115 K for this system. We observe 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 oscillator 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 recording ultrafast time-and-space-domain holograms. Spectral hole burning with femtosecond pulses was achieved.