论文标题
Simons天文台：大孔径氧化铝光学器件的宽带超材料抗反射插件
Simons Observatory: Broadband Metamaterial Anti-Reflection Cuttings for Large Aperture Alumina Optics
论文作者
论文摘要
我们介绍了用于在Simons天文台（SO）上部署的大量氧化铝过滤器（SO）的大幅面氧化铝过滤器的超材料反射插条（ARC）的设计，制造和测量的性能。 ARC由以近微米精度的自定义DICING SAW为单位的次波长组成。这些设计以高达20 $^\ Circ $的入射角对反射的百分比控制。在覆盖75-170 GHz频段的四个42 cm直径过滤器上证明了弧线，并且直径为50 mm的原型覆盖了200-300 GHz频段。这些样品的反射和传输是使用宽带相干源测量的，该宽带相干源涵盖了20 GHz至1.2 THz的频率。这些测量结果表明，随着波长接近超材料结构的长度尺度，散射占主导地位的光学响应时，随着波长接近传播的长度尺度，对靶向传递的反射率的百分比控制百分比控制。后一种行为使在此极限下将超材料弧作为散射过滤器的使用。
We present the design, fabrication, and measured performance of metamaterial Anti-Reflection Cuttings (ARCs) for large-format alumina filters operating over more than an octave of bandwidth to be deployed on the Simons Observatory (SO). The ARC consists of sub-wavelength features diced into the optic's surface using a custom dicing saw with near-micron accuracy. The designs achieve percent-level control over reflections at angles of incidence up to 20$^\circ$. The ARCs were demonstrated on four 42 cm diameter filters covering the 75-170 GHz band and a 50 mm diameter prototype covering the 200-300 GHz band. The reflection and transmission of these samples were measured using a broadband coherent source that covers frequencies from 20 GHz to 1.2 THz. These measurements demonstrate percent-level control over reflectance across the targeted pass-bands and a rapid reduction in transmission as the wavelength approaches the length scale of the metamaterial structure where scattering dominates the optical response. The latter behavior enables the use of the metamaterial ARC as a scattering filter in this limit.
