Golec Joseph E, Sutariya Shreya, Jackson Rebecca, Zimmerman Jerry, Dicker Simon R, Iuliano Jeffrey, McMahon Jeff, Puglisi Giuseppe, Tucker Carole, Wollack Edward J
Appl Opt. 2022 Oct 20;61(30):8904-8911. doi: 10.1364/AO.472459.
We present the design, fabrication, and measured performance of metamaterial antireflection cuttings (ARCs) for large-format alumina filters operating over more than an octave of bandwidth to be deployed at the Simons Observatory (SO). The ARC consists of subwavelength features diced into the optic's surface using a custom dicing saw with near-micrometer accuracy. The designs achieve percent-level control over reflections at angles of incidence up to 20. The ARCs were demonstrated on four 42 cm diameter filters covering the 75 to 170 GHz band and a 50 mm diameter prototype covering the 200 to 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 use of the metamaterial ARC as a scattering filter in this limit.
我们展示了用于在超过一个倍频程带宽上运行的大幅面氧化铝滤光片的超材料抗反射切割（ARC）的设计、制造和测量性能，这些滤光片将部署在西蒙斯天文台（SO）。ARC由使用具有近微米精度的定制切割锯切割到光学表面的亚波长特征组成。这些设计在入射角高达20°时实现了对反射的百分比级控制。在四个直径为42厘米、覆盖75至170吉赫兹频段的滤光片以及一个直径为50毫米、覆盖200至300吉赫兹频段的原型上展示了ARC。使用覆盖20吉赫兹至1.2太赫兹频率的宽带相干源测量了这些样品的反射和透射。这些测量结果表明，在目标通带内对反射率实现了百分比级控制，并且随着波长接近超材料结构的长度尺度（此时散射主导光学响应），透射率迅速降低。后一种行为使得在这个极限情况下可以将超材料ARC用作散射滤光片。
