Optical lifetime and linewidth studies of the 7F0→5D0 transition in EuCl3·6H2O: A potential material for quantum memory applications

► The optical lifetime of EuCl3·6H2O increases 20 times with full deuteration. ► An optical coherence time of 740μs was observed in EuCl3·6D2O. ► High D purity EuCl3·6H2O is a good candidate material for quantum memories.