Hyperfine structure of theD21−H43levels ofPr3+: LaF3with the use of photon echo modulation spectroscopy

Abstract
We have performed a photon echo modulation measurement of the D21H43 levels of Pr3+: LaF3. This time-domain method yields a precise determination of the D21 excited-state hyperfine splittings and linewidths. New information on the relative orientation of the principal axes of the excited- and ground-state hyperfine Hamiltonians is presented.