NEW STANDARD FOR HIGH-TEMPERATURE PERSISTENT-HOLE-BURNING MOLECULAR MATERIALS - ALUMINUM PHTHALOCYANINE TETRASULFONATE 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 l east important of these are efficient hole burning, high storage densi ty in the frequency domain, resilience against destructive readout, an d operation at high temperatures (greater than or equal to 77 K). It i s shown that aluminum phthalocyanine tetrasulphonate (APT) in buffered hyperquenched glassy water (HGW) is a material whose hole-burning pro perties exceed, in every category, those of previously studied molecul ar systems. Its attributes at 77 K include a frequency storage-density parameter (ratio of the inhomogeneous broadening to the homogeneous w idth 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 w ith a fractional depth of 0.1, and a quite impressive resilience again st destructive readout from hole burning and light-induced hole fillin g. It was predicted, for APT in deuterated HGW, that similar to 10(8) digital readouts could be executed before refresh was necessary. The m echanism for hole burning of APT in HGW is nonphotochemical, a one-pho ton process. The results argue against the notion that only two-photon gated hole-burning materials bold promise for memory/processing appli cations. Although HGW is not a practical host medium for devices, a bi omolecular strategy for the design of materials that might be and that retain the exceptional hole-burning properties of APT in HGW is propo sed. In this regard, the first demonstration of hole burning in Jello is presented. (C) 1997 Optical Society of America.