Optical Modulation of Anti-Stokes Luminescence in CaF2:Er Crystals

Emission and visible photoluminescence excitation spectra of CaF2:Er (0.5 at %) crystals have been studied under different optical pumping conditions. The results demonstrate that anti-Stokes luminescence of the erbium-doped crystals has higher intensity in the case of pumping of the 4I13/2 metastable state of the dopant. Resonance IR photon wavelengths have been determined for two-photon excitation of visible emission in CaF2:Er. A method has been developed for the optical modulation of anti-Stokes luminescence, which allows the nature of the corresponding electron transitions in emission centers to be identified.