Hyperfine interaction in ground and excited states of praseodymium-doped yttrium orthosilicate

We present characterization of the hyperfine interaction for the ground (H-3(4)) and one optically excited state (D-1(2)) of praseodymium impurities in a yttrium orthosilicate crystal. The Zeeman and pseudoquadrupole tensors were inferred by measuring the hyperfine splittings while rotating the direction of a weak (similar to40 G) magnetic field. The hyperfine spectra were recorded using Raman-heterodyne spectroscopy, a rf-optical double resonance technique.