An optical element including an optically transparent lens which defines a curved surface having a steepness given by an R/# of from about 0.5 to about 1.0. A film is positioned on the curved surface. The film includes an index layer. A composite layer is positioned on the curved surface having a refractive index greater than the index layer. The composite layer includes HfO2 and Al2O3. The composite layer has a mole fraction X of HfO2, wherein X is from about 0.05 to about 0.95 and a mole fraction of Al2O3 in the composite layer is 1−X.