Development and manufacture of laser mirror coatings for future gravitational wave observatories and other space applications

为了真正开拓引力波天文学的新领域，需要进一步提高引力波探测器的灵敏度。其中一个最具挑战性的领域是减少与干涉检测系统中使用的激光反射镜涂层相关的热驱动运动（布朗热噪声）。斯特拉斯克莱德大学和苏格兰国家制造研究所（NMIS）已经建立了新的ECR（电子回旋共振）离子束沉积技术，此外还采购了业界最好的RF（射频）离子沉积技术。该项目将寻求研究射频和ECR离子束系统。特别感兴趣的是研究使用新型氧化物混合物来增强用于超窄线宽腔的多层反射镜涂层的光学和机械性能。除此之外，基于最近在其他地方和LIGO科学合作组织（LSC）（包括Strathclyde和其他英国团体）进行的研究，该项目将研究新的退火方法，以通过扩散去除这些涂层中被困的惰性气体。目前已知，制造过程中需要捕获的气体会导致激光损伤敏感性增加，此外，在高温退火过程中还会导致气体聚集，从而导致起泡和应力诱导损伤。

Future improvements to gravitational wave detector sensitivities are required to truly exploit the new field of gravitational wave astronomy. One of the most challenging areas is reducing thermally driven motion (Brownian thermal noise) associated with the laser mirror coatings used in the interferometric detection system. The University of Strathclyde and the National Manufacturing Institute Scotland (NMIS) have established novel ECR (electron cyclotron resonance) ion beam deposition, in addition to procuring the industry-best RF (radio frequency) ion deposition technology. This project will seek to study both RF and ECR ion beam systems. Of particular interest is studying the use of novel oxide mixtures to enable enhanced optical and mechanical properties of multi-layer mirror coatings for use in ultra-narrow linewidth cavities. Beyond this, based on recent research carried out elsewhere and within the LIGO Scientific Collaboration (LSC) (which includes Strathclyde and other UK groups), the project will investigate novel annealing approaches for removing (by diffusion) the trapped inert gas within these coatings. Trapped gas, which is required in the manufacturing process, is now known to cause increased laser damage susceptibility, in addition to causing gas aggregation during the required high-temperature annealing that can cause blistering and stress-induced damage.