Phonon-assisted anti-Stokes excitation of the fluorescence of Mn2+ ions in the CsMnCl3•2H2O crystal

We demonstrate that anti-Stokes excitation of Mn2+ ions in the CsMnCl3. 2H(2)O crystal can occur through multiphonon addition to the energy of the photons of exciting light. The deficit dE between the energy of the Mn2+ T-4(1) exciton and the photon energy of the He-Ne laser used as the source of illumination is compensated by simultaneous annihilation of several thermally activated lattice phonons. The absence of two-photon activation of the fluorescence was verified by measurement of the dependence of the fluorescence intensity on the intensity of the exciting light, which appears linear at a fixed energy mismatch dE. (C) 2000 American Institute of Physics. [S1063-777X(00)00507-7].