OPTICAL SPECTROSCOPY OF A CR-3+-DOPED (GD, CA)3(GA, MG, ZR)2GA3O12 GARNET

In a gadolinium gallium garnet GGG crystal substituted by different cations (Ca**2** plus , Mg**2** plus , Zr**4** plus ) we have studied the optical properties of Cr**3** plus -doping ions and compared them with those of Cr**3** plus -doped Gd//3(Ga, Sc)//2Ga//3O//1//2 (GSGG). At room temperature the **4T//2 yields **4A//2 band is observed with a maximum at 7500 A. At 4. 4 K the **2E yields **4A//2 line and the **4T//2 yields **4A//2 band are superposed. The important inhomogeneous broadening of the line and non-exponential fluorescence decays as well as excitation and FLN spectra show that the Cr**3** plus ions are located in multisites of different intermediate crystal field strengths.