AI 中文总结
该研究针对用于引力波探测器的GaAs/AlGaAs高反射镜涂层，采用低温多模态柔性节点悬挂系统首次测量其低温机械损耗，为理解涂层热噪声的基本损耗机制提供了关键实验依据。
AI 中文摘要
具有极低热噪声的光学涂层对基于激光的高精度计量实验至关重要。衬底转移型晶体GaAs/Al₀.₉₂Ga₀.₀₈As涂层在λ=900nm至12μm的高反射镜涂层中具有最低的热噪声。时频稳定实验已证实，GaAs/AlGaAs反射镜涂层的噪声本底低于非晶反射镜涂层。目前，这类反射镜正被开发成尺寸≥300mm的产品，用于引力波探测器。为理解导致热噪声的涂层基本损耗机制，研究人员采用低温多模态柔性节点悬挂系统（工作温度范围为12K至室温），首次测量了该涂层在低温下的机械损耗。本次初始测量使用了硅衬底，其不对称性导致与节点支撑产生额外摩擦。通过对该摩擦及衬底和涂层中的Akhiezer损耗进行校正后，机械损耗与使用GaAs/AlGaAs反射镜的低温固定腔实验中观测到的热噪声吻合良好。
英文摘要
Optical coatings with minimal thermal noise are essential for high-precision, laser-based metrology experiments. Substrate-transferred crystalline GaAs/Al$_{0.92}$Ga$_{0.08}$As coatings have the lowest thermal noise for high-reflectivity mirror coatings with $λ=900$ nm -- 12 $μ$m. Time-frequency stabilization experiments have demonstrated that GaAs/AlGaAs mirror coatings have a lower noise floor than amorphous mirror coatings. These mirrors are now being developed at sizes $\ge 300$ mm for gravitational-wave detectors. In order to understand the coating's fundamental loss mechanisms, which cause thermal noise, we have performed the first measurement of the mechanical loss at cryogenic temperatures using a cryogenic, multimodal, gentle nodal suspension system, which operates from 12 K to room temperature. This initial measurement used a silicon substrate whose asymmetry produced excess friction with the nodal support. Accounting for this friction and Akhiezer loss in the substrate and coating, the mechanical loss agrees well with the thermal noise observed in experiments using cryogenic fixed-cavities with GaAs/AlGaAs mirrors.
Comments10 pages, 11 figures, To be submitted to Physical Review D
