Optical modulation of anti-Stokes photoluminescence of the Y$_2$O$_2$S : Er

The luminescence and excitation spectra of visible photoluminescence of Y$_2$O$_2$ : Er ceramics (1 at.%) at different optical pumping have been studied. It is shown that the anti-Stokes luminescence of single crystals doped with erbium has a high intensity when pumping the metastable state $^4I_{13/2}$ of impurities. The resonant wavelengths of IR-photons for two-photon excitation of the visible glow Y$_2$O$_2$ : Er. are determined. A method of photooptical modulation of anti-Stokes luminescence has been developed, which makes it possible to determine the nature of the corresponding electronic transitions inside the excited glow centers.