Zero-phonon selective spectroscopy: where do we stand now?

It is pointed out that: (1) in the case of very narrow widths of zero-phono n lines it is no longer justified to ignore completely the recoil energy E- r of the absorbed or the emitted photon; for the visible spectral range E-r similar to kilohertz; (2) considering the promising features of quantum co mputing it would be fair to compare them with what is already realized in p ersistent spectral hole-burning (PSHB) holography. Some PSHB applications p robably prospective to reach commercial level are considered, e.g. bundles of activated optical fibers as PSHB memory; study and memorizing of deforma tion fields. (C) 2000 Elsevier Science B.V. All rights reserved.