HIGH-RESOLUTION SPECTROSCOPY OF HYPERFINE-STRUCTURE USING PHASE-CORRELATED 4-WAVE-MIXING

We have obtained high-resolution spectra of hyperfine transitions in an excited state (1D2) of Pr3+:YAlO3 using a novel four-wave-mixing technique. Subkilohertz resolution is obtained. The hyperfine transition line shapes are determined unambiguously, revealing an interesting effect of mutual-flip interaction between the \m = +/- 1/2> hyperfine states of the Pr ions and the host nuclear spins. The necessary conditions for obtaining laser-jitter-independent resolution in inhomogeneously broadened samples are discussed.