Abstract

The development of photochemical and photo-physical hole-burning as a high-resolution spectroscopic tool for solids has led to a better understanding of the dynamical processes involved in guest-light and guest-host interactions. The method allows one to select for study a single homogeneous packet from within the inhomogeneously broadened line. A number of techniques are available for the detection of spectral holes. Two standard techniques are transmission spectroscopy and fluorescence excitation with narrowband tunable dye lasers. These methods do not feature zero background so that detection of shallow holes is limited by the ability to remove large background signals. Recently, ultrasonic modulation of nonphotochemical holes in crystals was reported¹ and described as a phase-insensitive optical detector for ultrasonic waves in solids. This phenomenon relies on the shifting and splitting of optical absorption lines by interaction with a time-varying stress field.

© 1984 Optical Society of America