Purely electronic zero-phonon lines in optical data storage and processing.

Spectroscopies of matrix isolated species and impurity activated solids are close relatives. Both are among the well developing chapters of solid state spectroscopy and optics. In this paper I am trying to give very brief overview what has been achieved in science and applications of impurity activated solids based on zero-phonon lines (ZPLs) in optical data storage and processing. I would like to show that the latter comprises via persistent spectral hole burning time-and-space domain holography in a certain meaning also the "stopping of light". ZPLs are beginning to play a role in the approaches to optical quantum computing.