OBSERVATION OF THE E-1 STATE OF CR4-ALUMINUM-GARNET( IN YTTRIUM)

High-pressure studies of the near-infrared; fluorescence of Cr4+:yttri um aluminum garnet (YAG) at 40 K have been used to induce a T-3(2)-E-1 crossover above 200 kbar and have permitted the observation of E-1--> (3)A(2) emission. The E-1-->(3)A(2) emission band is narrow, occurs ne ar 1100 nm, and shows a small redshift expected for a spin-flip transi tion. The energy of the emission is similar for different Cr4+ centers present in YAG; A preliminary lifetime measurement of the E-1-->(3)A( 2) emission of the principle Cr4+ Site at similar to 270 kbar and 40 K yields a value of similar to 250 mu s, and an similar to eightfold in crease relative to the value at ambient pressure and 40 K.