Understanding the fundamental limits for laser/optical mirror fabrication is directly relevant to the development of mirrors with improved durability and damage thresholds. Ag layers deposited in ultra-high vacuum on a well characterized, single-crystal Cu(llO) substrate as a function of substrate temperature have been analyzed using Auger electron spectroscopy (AES) and low-energy electron diffraction (LEED) in order to answer questions concerning substrate overlayer formation and film degradation at the early stages of growth (̃ 10 monolayers).

Another aspect of this work has centered on developing diagnostics transferable from UHV to “real-world” environments. Optical second-harmonic generation (SHG) was chosen due to its surface specificity and experimental simplicity. The observed SH intensity as a function of Ag deposition even at submonolayer coverages. A comparison between the observed SH intensity and polarization dependence with the AES and LEED analysis indicates that optics SHG provides a fingerprint of the nucleation of Ag clusters.