From color centers to coherent phonon states

The author traces the progression of scientific steps which start with color centers in alkali halides and ends with his current research on the coherent generation and dephasing of vibrations in solids. Among the observed phenomena are crystal field splitting of atomic states in ionic materials; localized and extended phonon states in alkaline-earth halides, and other insulators; spectral, spatial and temporally resolved phonon transport in various materials, the generation of coherent phonon and polariton states in semiconductors, and the dephasing of the coherent states and the observations of a long sought after long-lived phonon state. (author)