Photoluminescence spectroscopy of Cr3+ in CaY2Mg2Ge3O12

We have conducted a thorough investigation of the luminescence spectrum of Cr3+ in CaY2Mg2Ge3O12. The spectrum presents a line whose width is 60 cm−1 at 25 K and 82 cm−1 at 200 K, and a number of peaks of vibronic origin superimposed on a large band that extends from 700 to 800 nm. Going up in temperature the superimposed peaks broaden and disappear while the band persists. The response of the system to pulsed excitation presents at low temperature a great variety of patterns at different wavelengths. These patterns tend to collapse into one as the temperature is raised. This investigation confirms that the continuous interest in Cr-doped garnets is rewarding in terms of interesting experimental results.