Rare earth-based low-index films for IR and multispectral thin film solutions

Non-thoriated rare-earth fluoride based coating solutions involving DyF₃ and YbF₃ based films as well as non-wetting fluorohydrocarbon cap layers on such films, have been deposited, analyzed and partly optimized. Intermediate results for DyF₃ based films from ion assisted e-gun deposition with O₂ and N₂ alone and as base for the non-wetting to-player as well as for YbF3 starting material with or without admixtures of CaF₂ are discussed for low-loss LWIR and multispectral solutions.