A deeper focus on the primordial universe: Development of a metamaterial-based lenslet coupled with kinetic inductance detectors for Cosmology.

宇宙微波背景辐射偏振态的测量是目前宇宙学研究的热点之一。特别是，相关的原始b模的检测是目前该领域的挑战。物理与天文学院的天文仪器小组参与了世界范围内许多以探测b模式为目标的项目。b模信号非常微弱，需要具有非凡灵敏度的仪器和对光学系统效应的精细控制。高灵敏度可以通过使用数千个探测器耦合到非常紧凑的像素/天线阵列来实现。目前基于“透镜”阵列的解决方案依赖于小而非常弯曲的透镜，这些透镜不易制造，并且需要专门设计的抗反射涂层才能有效工作。在这个项目中，我们提出了基于超材料的高性能和紧凑的透镜阵列。天文仪器集团是世界领先的设计和生产基于“网格过滤器”技术的准光学设备。我们最近开发了扁平的“网格透镜”，能够准确地模仿较厚的标准透镜的行为。这些透镜可以“小型化”，并与探测器阵列耦合。网格透镜阵列可以是一个包含所有小透镜的简单平面装置。这些阵列的建模和设计将通过电磁有限元分析（Ansys HFSS）进行。设备将在集团洁净室和实验室内制造和测试。电磁特性将通过傅里叶变换光谱仪（FTSs）和矢量网络分析仪（vna）进行。这项工作还将与科罗拉多大学和美国国家标准与技术研究所（NIST）合作进行。博士研究项目将包括：-使用有限元分析软件（HFSS）的超材料电磁建模-基于超材料的新型透镜阵列的设计和优化-协助在集团设施内制造设备-使用傅里叶变换光谱仪和矢量网络分析仪进行设备测试-分析和解释数据

Measurements of the polarisation states of the Cosmic Microwave Background (CMB) radiation is currently one of the hottest topics in Cosmology. In particular, the detection of the associated primordial B-modes is the present challenge in this field. The Astronomy Instrumentation Group, within the School of Physics and Astronomy, is involved in many projects world-wide targeting the detection of the B-modes. The B-mode signals are extremely weak and require instrumentation with extraordinary sensitivity and exquisite control of the optical systematic effects. High sensitivity can be achieved by using thousands of detectors coupled to very compact arrays of pixels/antennas. Current solutions based on 'lenslet' arrays rely on small and very-curved lenses which are not easy to manufacture and require specifically designed anti-reflection coatings to work efficiently. In this project we propose to develop high performance and compact lenslet arrays based on metamaterials. The Astronomy Instrumentation Group is world-leading in the design and production quasi-optical devices based the 'mesh-filters' technology. We have recently developed flat 'mesh-lenses' able to accurately mimic the behaviour of thicker standard lenses. These lenses can be 'miniaturised' and coupled to array of detectors. A mesh-lens array can be a simple flat device which includes all the small lenses.The modelling and the design of these arrays will be carried out by using electromagnetic finite element analysis (Ansys HFSS). The devices will be manufactured and tested within the group cleanrooms and laboratories. The electromagnetic characterisation will be performed with Fourier Transform Spectrometers (FTSs) and Vector Network Analysers (VNAs).The work will be carried out also in collaboration with the Colorado University and the National Institute of Standard and Technology (NIST).The PhD research project will consist of:- Metamaterials electromagnetic modelling using finite-element analysis software (HFSS)- Design and optimisation of a novel lenslet array based on metamaterials- Assistance in the manufacture of the device within the group facilities- Device testing with Fourier Transform Spectrometers and Vector Network Analysers- Analysis and interpretation of the data