Nonlinear Excitation of New Emission Bands in Kcl Crystals Containing Color Centers

Abstract

New luminescence bands are observed in KCl containing F and F-aggregate centers under strong excitation with an infrared laser. All these emission bands occur a t energies higher than those of the pumping beam. These "up-conversion" emissions are assigned to transitions from higher excited states of color centers populated by means of multiphoton absorption. Specific relations between the centers and the emission bands are also discussed.

Dynamics of nuclear wave packets at theFcenter in alkali halides

“…The fact that the 2s state lies higher than the 2p state in the FCS but is lower in the RES indicates that the 2s and 2p levels cross between the two states, so that a dynamic nonradiative transition is expected to occur. In order to detect the presence of the 2s-2p level crossing, resonant secondary radiation (RSR) spectra have been measured under the conditions of one-photon excitation (1s-2p transition) [45][46][47][48][49][50][51][52][53] and twophoton excitation (1s-2s transition) [88][89][90][91], and numerical calculations based on the RSR theory have been done [92,93]. (A framework of the RSR theory is described in appendix A.)…”