Photon-gated spectral holeburning

Photon-gated spectral holeburning uses two photons to bleach a narrow hole in an inhomogeneously broadened absorption. A brief review is given of the inorganic and organic materials known to exhibit this phenomenon, with emphasis on the inorganic systems BaClF+, CaF2+, LiGa5O8+ and SrTiO3+. In all these cases photoionization of the impurity ion is believed to be the mechanism of photobleaching. © 1987.