Probing hyperfine interactions in 53Cr(III) doped Al2O3 by spectral hole-burning in low magnetic fields

We report transient spectral hole-burning experiments conducted in the R1(±1/2) line of 53-chromium(III) doped Al2O3 in zero field and low magnetic fields B∥c at 3 K. These facile experiments enable, in principle, the simultaneous determination of the hyperfine coupling parameters for both the 4A2 ground state and the excited state, and in both directions to the crystal caxis. In order to determine these parameters we have applied a global fit by simulated spectra to the experimental data and good agreement between calculated and measured hole-burning patterns is achieved. The relevant resulting parameters for the excited state are A∥=18±4 MHz and A⊥=40±4 MHz.