Hole-Burning of Dye-Molecules Adsorbed on Metal Oxide Powders,

First preliminary persistent spectral hole-burning PSHB investigations of dye-molecules adsorbed onto the disordered surfaces of metal oxides powders of porous glasses indicated that these systems seem to behave quite similar to doped glasses. The optical absorption is strongly inhomogeneously broadened due to the disorder of the surface and at 1.5 K holewidths in the 1 cm range-even an order of magnitude broader than in glasses - have been reported. In the following we will give a short summary of our latest more detailed investigations of surface adsorbed dye-molecules which on the one hand reaffirm that theses systems indeed behave in many respects as 3-D disordered systems but on the other hand point to some remarkable specific features of adsorbed dye-molecules.