Effect of deposition rate on the DUV/VUV reflectance of MgF2 protected aluminum mirrors with e-beam evaporation

Aluminum mirrors were freshly fabricated under optimum conditions protected with MgF 2 at various deposition rates which evaporated by e-beam. All the samples were deposited on fine polished fused silica substrate. The reflectance results were measured by Mcpherson Vuvas2000 spectrometer in DUV/VUV spectral region from 150nm to 350nm. The highest reflectance is chosen to 210nm, and the point of 160nm is also very important for the project, so the results of two points are detailed presented. The highest average reflectance is about 86.76% with the MgF 2 deposition rate at 1.2nm/s. The effects of aging on the reflectance of the MgF 2 protected aluminum mirrors are discussed.