Uncoated surfaces of high index glasses when cemented to form lens doublets have inferior antireflection properties to doublets of low index glass. This can be overcome by the application of a single layer coating of aluminum oxide prior to cementing.
© 1990 Optical Society of America.
Ronald R. Willey, "Antireflection coating for high index cemented doublets," Appl. Opt. 29, 4540-4541 (1990)