Feature

Persistent Infrared Spectral Hole Burning

A.J. Sievers

In 1974, persistent spectral holes were first produced in the inhomogeneous electronic transitions in solids. To this day, persistent spectral features caused by both photochemical and non-photochemical processes are found in ever increasing numbers. In the 1980s, low frequency analogues of these processes were discovered and explored. Persistent IR spectral holes can be generated in the vibrational degrees of freedom of molecular defects in crystals and glasses even though no electronic excitation is involved, i.e., a non-photochemical process. The brief overview of these findings presented below demonstrates that such persistent IR spectral holes do provide a new high resolution technique with which to explore the dynamics of vibrational defects in solids, as well as the properties of the solids themselves.