Fluorescence line narrowing in Cr3+-doped gallium gadolinium garnet under a magnetic field

Fluorescence-line-narrowing experiments have been performed on the Cr3+-ion R line in Gd3Ga5O12 (GGG) under a magnetic field. In this system the spin-spin interaction between Cr3+ and Gd3+ ions precludes conventional line narrowing, so that the use of a magnetic field becomes necessary. At 4.5 T we have found a narrowed width of 0.8 cm-1, as compared with the 6.2-cm-1 width at 0 T. The emission spectra are interpreted with contributions ascribed to different chromium sites. © 1991 The American Physical Society