Photon Echoes in Trivalent Neodymium.

Ying Chih Whitney Chen

Ralph R. Jacobs, W.F. Krupke

Sergey M. Zakharov, Edward A. Manykin

R. M. Macfarlane

Photon-echo measurements are reported for the trivalent thulium ion, which differs from all other rare-earth ions in having a single isotope of nuclear spin 1/2. Echo decays on the 3H6(1) ↔ 3H4(1) transition of LaF3:Tm3+ and YAG:Tm3+ were magnetic-field dependent at 1.5 K, showing that the dephasing originates from spin fluctuations of nuclei in the host crystals. Coherence times in the range of 7 to 100 μs were measured, corresponding to homogeneous linewidths of tens of kilohertz. The echo decays were nonexponential, providing evidence for spectral diffusion that is due to a distribution of 19F and 27A1 nuclear spin-flip times in the respective hosts.

Swapan Kumar Gayen, Bin Qing Xie

Resonantly enhanced, near-ultraviolet 4f3 → 4f25d two-photon transitions have been observed in trivalent neodymium-doped yttrium aluminum garnet (Nd3+:Y3Al5O12). The two-photon excitation spectra over the 40 400–46 730 cm−1 transition energy range are characterized by sharp resonance peaks on a slowly varying background caused by nonresonant transitions. The peak two-photon cross section involving the 2P1/2 resonant intermediate state is 9 × 10−51 cm4 s, and the integrated cross section is 2.2 × 10−38 cm4.

Robert J. Nordstrom, W.M. Gutman, C. V. Heer