No abstract

The technique of liquid phase epitaxy has been used to produce single-crystal garnet phosphor screens for cathode ray tubes. The films were rare-earth-doped yttrium aluminum garnets (YAG’s) grown onto YAG substrates using a PbO:B2O3 flux. We have studied the light output of these layers as a function of film growth temperature, rare-earth activator concentration, and incident power density. With Ce:YAG layers it was possible to use beam power densities up to 108 W/m2 and this produced a radiance of over 105 W/cm2 sr.

No abstract

The intensity of luminescence in YAG, activated with rare-earth ions, shows a nonlinear behavior as a function of incident current density under electron bombardment. Tb3+ or Eu3+ activated samples exhibit deviation from linearity at input power densities exceeding 104 W/m2, while Ce3+ luminescence is linear up to the highest power densities studied (108 W/m2). It is shown that nonlinearity effects, in cases where temperature quenching can be excluded, are caused by saturation of the excited-state population. The results are interpreted in a model which also takes into account excited-state absorption within one activator and energy transfer between neighboring activator ions.