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Highly Efficient 1.3-µm Luminescence from Rare-earth-doped Halides Prepared from Low Temperature Aqueous Solutions

John Ballato, Richard E. Riman, Elias Snitzer

The tremendous growth in photonic materials and device research results largely from the explosion in telecommunications, including the traffic requirements needed for the Internet and future interactive video and multimedia services. These trends have motivated a global search for materials suitable for optical amplification at the 1.3-μm zero dispersion wavelength, which maximizes the information carrying capacity of silica fibers. Praseodymium (Pr3+) has received the most attention as a dopant for gain at 1.3 μm and has reached some level of commercialization despite a relatively low quantum yield from the requisite nonoxide glass hosts (~10 %). Dysprosium (Dy3+) has also attracted recent interest since its absorption cross-section is larger than Pr3+ thus lessening the requisite amplifier length. In both cases, maximizing the luminescence efficiency requires hosts with low phonon energies. Accordingly, we considered the solution-synthesis of doped-lanthanum halides because of their low phonon energy and high rare-earth solubility.