Two-photon transitions of Ag−centers in KBr

Abstract Two-photon excitation spectra of Ag− centers in KBr have been measured. The main excitation peak appears only with linearly polarized excitation and has been assigned to the 1A1g → 1A1g transition. Weaker structures have a polarization dependence corresponding to 1A1g → 1E g and 1A1g → 1T2g transitions.