论文标题
宽带多层抗反射涂层，带有Mullite和Duroid，用于半波板和氧化铝过滤器，用于CMB极化法
Broadband multi-layer anti-reflection coatings with mullite and duroid for half-wave plates and alumina filters for CMB polarimetry
论文作者
论文摘要
开发了宽带两层抗反流（AR）涂层，用于蓝宝石半波板（HWP）和用于宇宙微波背景（CMB）偏光仪的氧化铝红外（IR）滤光片。测量微小的CMB B模式信号需要最大程度地提高到达检测器的光子数量，并最大程度地降低了由于反射轴的入射角的反射而导致的伪造极化。但是，蓝宝石HWP和氧化铝IR过滤器的折射率高约为3.1，并且必须在其上施加AR涂层。选择热喷涂的mullite和Duroid 5880Lz，根据指数和热膨胀系数在低温温度下使用。使用这些材料，在90/150 GHz时，反射率降低到约2％，在220/280 GHz时<1％。描述了AR涂料的设计，制造和光学性能评估。涂料用于当前的地面CMB实验，称为Simons阵列。它们也可以应用于下一代CMB实验，例如Simons天文台。
A broadband two-layer anti-reflection (AR) coating was developed for use on a sapphire half-wave plate (HWP) and an alumina infrared (IR) filter for cosmic microwave background (CMB) polarimetry. Measuring tiny CMB B-mode signals requires maximizing the number of photons reaching the detectors and minimizing spurious polarization due to reflection with an off-axis incident angle. However, a sapphire HWP and an alumina IR filter have high refractive indices of about 3.1, and an AR coating must be applied to them. Thermally sprayed mullite and Duroid 5880LZ were selected in terms of index and coefficient of thermal expansion for use at cryogenic temperatures. With these materials, the reflectivity was reduced to about 2% at 90/150 GHz and <1% at 220/280 GHz. The design, fabrication, and optical performance evaluation of the AR coatings are described. The coatings were used in a current ground-based CMB experiment called the Simons Array. They could also be applied to next-generation CMB experiments, such as the Simons Observatory.
