Fernández-Perea Mónica, Larruquert Juan I, Aznárez José A, Pons Alicia, Méndez José A
GOLD, Instituto de Física Aplicada-Consejo Superior de Investigaciones Científicas, C/Serrano 144, 28006 Madrid, Spain.
Appl Opt. 2007 Aug 1;46(22):4871-8. doi: 10.1364/ao.46.004871.
Ion-beam sputtering (IBS) and evaporation are the two deposition techniques that have been used to deposit coatings of Al protected with MgF(2) with high reflectance in the vacuum ultraviolet down to 115 nm. Evaporation deposited (ED) Al protected with IBS MgF(2) resulted in a larger (smaller) reflectance below (above) 125 nm than the well-known all-evaporated coatings. A similar comparison is obtained when the Al film is deposited by IBS instead of evaporation. The lower reflectance of the coatings protected with IBS versus ED MgF(2) above 125 nm is because of larger absorption of the former. Both nonprotected IBS Al, as well as IBS Al protected with ED MgF(2), resulted in a band of reflectance loss that was peaked at 127 and 157 nm, respectively. This result was attributed to the excitation of surface plasmons due to the enhancement of surface roughness with large spatial wave vectors in the sputter deposition. This reflectance loss for IBS Al protected with MgF(2) is small at the short (lambda~120 nm) and long (lambda<350 nm) wavelengths investigated. IBS Al protected with ED MgF(2) is thus a promising coating for these two spectral regions. Coatings protected with IBS MgF(2) resulted in a reflectance as high as coatings protected with ED MgF(2) at wavelengths longer than 550 nm, whereas the former had a lower reflectance below this wavelength.
离子束溅射（IBS）和蒸发是两种已被用于沉积在真空紫外波段低至115纳米具有高反射率的MgF₂保护的Al涂层的沉积技术。用IBS MgF₂保护的蒸发沉积（ED）Al在125纳米以下（以上）的反射率比著名的全蒸发涂层更大（更小）。当Al膜通过IBS而非蒸发沉积时，可得到类似的比较结果。IBS保护的涂层在125纳米以上相对于ED MgF₂保护的涂层反射率较低是因为前者有更大的吸收。未保护的IBS Al以及用ED MgF₂保护的IBS Al都导致了反射率损失带，分别在127和157纳米处达到峰值。该结果归因于在溅射沉积中具有大空间波矢的表面粗糙度增强导致的表面等离子体激元的激发。在研究的短波长（λ~120纳米）和长波长（λ<350纳米）下，用MgF₂保护的IBS Al的这种反射率损失较小。因此，用ED MgF₂保护的IBS Al对于这两个光谱区域是一种有前景的涂层。在波长大于550纳米时，用IBS MgF₂保护的涂层的反射率与用ED MgF₂保护的涂层一样高，而在该波长以下前者的反射率较低。
