Optimization of scandia thin films for high power laser coating applications

We discuss the physical and optical properties of Sc2O3 single layers deposited by the dual ion beam sputtering technique at oxygen partial pressures ranging from 1.7×10-5 to 5.1×10-5 Torr. The films are amorphous with crystallite size ~10 nm and have surface roughness RMS values of 1.2±0.3 nm. The refractive index at 1 μm is 1.95. Absorption loss is shown to be sensitive to the oxygen partial pressure during growth. Multiple-pulse damage experiments suggest that the scandia film deposited at the higher oxygen partial pressure accumulates laser-induced trap defects more slowly than the scandia film deposited in a lower oxygen partial pressure atmosphere.

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