Infrared transmission of Na⁺-doped γ-La₂S ₃ ceramics densified by hot pressing

Na-doped γ -La₂S₃ powders with various Na/La ratios were synthesized by the gas-solid reaction method. Then they were sintered by hot pressing to study the effects of Na⁺ ions on the microstructures and optical properties of γ -La₂S₃ ceramics. A phase analysis indicated that the least appropriate Na+ dose to stabilize γ -La₂S₃ was Na/La = 1 : 20. IR transmission measurements showed that the pellet with Na/La = 1 : 20 had a higher infrared transmittance than other pellets, and the maximum transmittance reached 64.5% at 13μm, which was near the theoretical transmittance of a γ -La₂S₃ crystal.