Preparation and Characterization of Yb3+-Doped Metaphosphate Glasses for High Energy and High Power Laser Applications

Ytterbium-doped metaphosphate laser glasses were prepared by the melt-quenching technique and their optical, thermo-mechanical and laser properties were characterized. Linear and non-linear refractive indices, laser-induced damage threshold, microhardness number and thermal expansion co-efficient have been evaluated for 1.0 mol% Yb2O3-doped glass. Low non-linear refractive index, high laser-induced damage threshold and low thermal-expansion coefficient have been noticed. Vickers hardness (4.07 GPa) for the present glass is found to be higher than that of Schott (APG-1; 3.09 GPa) glass and comparable with the Hoya (HAP-4; 4.70 GPa) glass. Higher magnitudes of absorption cross-sections (4.49-1.47 x 10(-20) cm(2)), emission cross-sections (6.08-2.06 x 10(-20) cm(2)) at 975 nm and (1.28-0.63 x 10(-2) cm(2)) at 1.0 mu m have been found along with an acceptable bandwidth (52-58 nm) when the Yb2O3 concentration varied from 0.01 to 1.0 mol%. All the studies reveal that the Yb3+-doped metaphosphate laser glasses could be suitable as a gain media for high energy and high power laser applications at similar to 1.0 mu m region.