论文部分内容阅读
很早就认识到,在要求高的光学表面上,例如应用在光谱学中的卤化物晶体窗口或透镜,需要用保护层。很多广泛应用的卤化物材料,例如:氯化钠和碘化铯极易于潮解因而采用了很多方法保护上述的光学零件。这些方法都不够成熟,往往不可靠或不实用。己经证明,将单体氟化物用低温气体放电法(等离子体)聚合成1微米厚的有机薄膜,其抗潮性很高。例如,用它保护的碘化铯可达几百个小时,而没有保护的几分钟就破坏了。而且,这些膜层的折射率在卤化物基体和空气之间(这是增透的条件,是希望光学涂层具有的另一个性能)。因此,有机膜层不仅有保护作用,而且也提高了透过率。此外,除了8.0微米处外(由C-F键引起的吸收),聚合物膜层在0.4～40微米范围内无吸收。
It has long been recognized that over demanding optical surfaces, such as halide crystal windows or lenses used in spectroscopy, require a protective layer. Many widely used halide materials, such as sodium chloride and cesium iodide, are highly deliquescent and therefore employ many methods to protect the optical components described above. These methods are not mature enough, often unreliable or impractical. It has been shown that the monomeric fluorides are polymerized by low-temperature gas discharge (plasma) into organic films of 1 micrometer thick and have high moisture resistance. For example, the cesium iodide it protects can last up to hundreds of hours without destruction for a few minutes without protection. Moreover, the refractive index of these films is between the halide matrix and the air (this is the condition of seepage enhancement, which is desirable for the optical coating to have another property). Therefore, the organic film layer not only has a protective effect, but also improves the transmittance. In addition, except at 8.0 microns (Absorption due to C-F bonds), the polymer film layer has no absorption in the 0.4-40 micron range.