We used two novel approaches to produce sub-wavelength structure (SWS) anti-reflection coatings (ARC) on silicon for the millimeter and sub-millimeter (MSM) wave band: picosecond laser ablation and dicing with beveled saws. We produced pyramidal structures with both techniques. The diced sample, machined on only one side, had pitch and height of 350 $μ$m and 972 $μ$m. The two laser ablated samples had pitch of 180 $μ$m and heights of 720 $μ$m and 580 $μ$m; only one of these samples was ablated on both sides. We present measurements of shape and optical performance as well as comparisons to the optical performance predicted using finite element analysis and rigorous coupled wave analysis. By extending the measured performance of the one-sided diced sample to the two-sided case, we demonstrate 25 % band averaged reflectance of less than 5 % over a bandwidth of 97 % centered on 170 GHz. Using the two-sided laser ablation sample, we demonstrate reflectance less than 5 % over 83 % bandwidth centered on 346 GHz.
Silicon-based vacuum window for millimeter and submillimeter-wave astrophysics
Okayama University（冈山大学）；University of Minnesota, Twin Cities（明尼苏达大学双城分校）；The University of Tokyo（东京大学）；Delft University of Technology（代尔夫特理工大学）；Netherlands Institute for Space Research (SRON)（荷兰空间研究所）；Laser Zentrum Hannover（汉诺威激光中心）；Institute for Photon Science and Technology (IPST), The University of Tokyo（东京大学光子科学技术研究院）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo（东京大学宇宙物理数学研究所（WPI））；Center for Data Driven Discovery (CD3), Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo（东京大学宇宙物理数学研究所数据驱动发现中心）；ILANCE, CNRS, University of Tokyo International Research Laboratory（日本理化学研究所-东京大学国际联合实验室）
3D Printed Alumina as a Millimeter-Wave Optical Element
School of Physics and Astronomy, University of Minnesota（明尼苏达大学物理与天文学院）；Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo（东京大学宇宙物质研究宇宙线前沿国际中心）；Laser Zentrum Hannover e.V.（汉诺威激光中心）；Institute for Photon Science and Technology (IPST), The University of Tokyo（东京大学光子科学技术研究所）
Development and characterization of a millimeter-wave cold load prototype
Institutes of Physical Science and Information Technology, Anhui University（安徽大学物理科学与信息工程学院）；State Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所粒子天体物理国家重点实验室）；School of Physics and Materials, Nanchang University（南昌大学物理与材料学院）；School of Biomedical Engineering, Shanghai Jiao Tong University（上海交通大学医学院生物医学工程学科）；School of Mechatronics and Control Engineering, Shenzhen University（深圳大学机械与控制工程学院）；Center of Free Electron Laser and High Magnetic Field, Anhui University（安徽大学自由电子激光与强磁场中心）
