Luminescence behaviour of a Yb sensitized Er:YAG transparent ceramic prepared by the solid-state reaction method

Optical-grade yttrium aluminum garnet (YAG) ceramics co-doped with Yb3+ and Er3+ ions are successfully prepared via using high-temperature solid-state reaction method under vacuum condition. Cubic phase structure and full dense microstructure are determined by means of X-ray diffraction (XRD) and scanning electron microscope (SEM) methods. Both characteristics endow our ceramic with high optical transmittance of ~82% at 600 nm. Moreover, the ceramic luminescent properties are mainly discussed with Yb3+ ions serving as an efficient sensitizer for Er3+ active centers. Both zero-phonon lines (ZPLs) and sidebands of Er3+ ions in the YAG ceramics are first analyzed and the most interesting finding of this work is the anti-Stokes sidebands showing remarkably stronger emission intensity than Stokes ones. This obtained result reveals the predominance of absorbing phonon energy in vibronic luminescence process under the weak crystal field.