HOMOGENEOUS BROADENING AND HYPERFINE-STRUCTURE OF OPTICAL-TRANSITIONSIN PR3+Y2SIO5

Contributions to the homogeneous linewidth of the H-3(4)(1)-->D-1(2)(1 ) transition for the two crystallographic sites of Pr3+ in Y2SiO5 have been investigated using photon echoes. The effects of excitation-inte nsity-dependent dephasing or instantaneous diffusion were systematical ly studied to allow accurate determination of the optical resonance wi dths. Homogeneous linewidths of 2.8 kHz (site 1) and 1 kHz (site 2) we re measured with no applied magnetic held and with sufficiently low la ser intensity to minimize the effects of instantaneous diffusion. Usin g the same excitation intensity, widths of 2.1 kHz (site 1) and 0.85 k Hz (site 2) were obtained with an applied magnetic held of 77 G, demon strating a significant contribution of Y-89 nuclear-spin fluctuations to the zero-field homogeneous linewidth. Extrapolation to zero excitat ion intensity yielded optical resonance widths that were only slightly narrower than the measured values. Optically detected nuclear magneti c resonance measurements determined the hyperfine structure of the H-3 (4) ground state for each site; the hyperfine levels of the lowest com ponent of the D-1(2) manifold for each site were determined using phot on echo nuclear double resonance. The relatively large oscillator stre ngth of 3 X 10(-7) for a rare-earth ion, in conjunction with long deph asing times makes this material a useful candidate for demonstration o f time-domain signal processing and optical data storage.