New standard for high-temperature persistent-hole-burning molecular materials: Aluminum phthalocyanine tetrasulphonate in buffered hyperquenched glassy films of water

Applications of persistent spectral hole burning to optical memory and processing technologies currently face a number of hurdles. Not the least important of these are efficient hole burning, high storage density in the frequency domain, resilience against destructive readout, and operation at high temperatures (greater than or equal to 77 K). It is shown that aluminum phthalocyanine tetrasulphonate (APT) in buffered hyperquenched glassy water (HGW) is a material whose hole-burning properties exceed, in every category, those of previously studied molecular systems. Its attributes at 77 K include a frequency storage-density parameter (ratio of the inhomogeneous broadening to the homogeneous width of the zero-phonon line) of 125 (similar to 10(5) at 5 K), a burn fluence as low as 1.5 mJ/cm(2) for production of a zero-phonon hole with a fractional depth of 0.1, and a quite impressive resilience against destructive readout from hole burning and light-induced hole filling. It was predicted, for APT in deuterated HGW, that similar to 10(8) digital readouts could be executed before refresh was necessary. The mechanism for hole burning of APT in HGW is nonphotochemical, a one-photon process. The results argue against the notion that only two-photon gated hole-burning materials bold promise for memory/processing applications. Although HGW is not a practical host medium for devices, a biomolecular strategy for the design of materials that might be and that retain the exceptional hole-burning properties of APT in HGW is proposed. In this regard, the first demonstration of hole burning in Jello is presented. (C) 1997 Optical Society of America.