Growth and spectroscopy of lanthanide doped Y2SiO5 microcrystals for quantum information processing

Lanthanide-doped Y$₂$SiO$₅$ microcrystals were prepared using the solution combustion, solid state and sol-gel synthesis techniques. Of these, the sol-gel method yields the most reliable and high-quality X2 phase Y$₂$SiO$₅$ microcrystals. Absorption and laser site-selective fluorescence measurements of Nd$³⁺$, Eu$³⁺$ and Er$³⁺$ doped material, performed at cryogenic temperatures, indicate that the as-grown microcrystals are of high optical quality with inhomogeneously broadened optical linewidths that are comparable to bulk crystals at similar dopant concentrations.