Novel Transparent Ceramics Based on Tm3+-Doped Cubic Gadolinia and its Solid-Solutions for 2 µm Lasers

Transparent ceramics based on thulium-doped cubic gadolinia Gd 2 O 3 and its solidsolutions (Gd,Y) 2 O 3 , (Gd,Lu) 2 O 3 and (Gd,Y,Lu) 2 O 3 are fabricated by hot pressing. They feature low phonon energies and broad and smooth gain profiles extending above 2 μm.