A highly reflective mirror for use in the wavelength range of 0.300 μm to 15 μm includes a substrate, a first interface layer, a reflective layer, a second interface layer, a plurality of tuning layers including a combination of a low index material and a high index material wherein the high index material is HfO2, and a protective layer. The highly reflective mirror has a reflectivity of at least 90% over the wavelength range of 335 nm to 1000 nm at an angle of incidence (AOI) of 45°.