The quasi-optical design of the QUaD Telescope
The quasi-optical design of the QUaD Telescope
复制标题
QUaD 望远镜的准光学设计
DOI：
10.1117/12.551680
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发表时间：
2004
影响因子：
5
通讯作者：
M. Zemcov
中科院分区：
文献类型：
--
作者：
G. Cahill;C. O'sullivan;J. Murphy;W. Lanigan;E. Gleeson;P. Ade;J. Bock;M. Bowden;J. Carlstrom;S. Church;K. Ganga;W. Gear;J. Harris;J. Hinderks;Wayne Hu;J. Kovac;A. Lange;E. Leitch;B. Maffei;O. Mallie;S. Melhuish;A. Orlando;G. Pisano;L. Piccirillo;C. Pryke;B. Rusholme;A. Taylor;K. Thompson;M. Zemcov
QUaD是一种基于地面的高分辨率（高达l≈2500）仪器，旨在绘制宇宙微波背景的偏振图，并测量其e模和b模偏振功率谱。QUaD包括一个辐射热测量阵列接收器（100 GHz和150 GHz）和2.6米Cassegrain望远镜2上的再成像光学器件。它将运行两年，并于2005年开始观测。CMB偏振测量不仅需要比早期实验显著提高灵敏度，还需要更好地理解和控制系统效应，特别是那些导致极化信号的效应。为此，我们对QUaD望远镜进行了全面的准光学分析。特别地，我们模拟了衍射对光束通过系统传播的影响。将望远镜的辐射耦合到相敏辐射热计的波纹馈电需要具有良好的波束对称性和在所需带宽上的低旁瓣电平。特别重要的是馈入角保持入射场的极化方向。我们使用了精确的模式匹配模型来设计这种馈电喇叭。本文介绍了QUaD前端光学器件的衍射分析，以及QUaD波形馈源的电磁设计和测试。
QUaD is a ground-based high-resolution (up to l ≈ 2500) instrument designed to map the polarisation of the Cosmic Microwave Background and to measure its E-mode and B-mode polarisation power spectra. QUaD comprises a bolometric array receiver (100 and 150 GHz) and re-imaging optics on a 2.6-m Cassegrain telescope 2. It will operate for two years and begin observations in 2005. CMB polarisation measurements will require not only a significant increase in sensitivity over earlier experiments but also a better understanding and control of systematic effects particularly those that contribute to the polarised signal. To this end we have undertaken a comprehensive quasi-optical analysis of the QUaD telescope. In particular we have modelled the effects of diffraction on beam propagation through the system. The corrugated feeds that couple radiation from the telescope to phase-sensitive bolometers need to have good beam symmetry and low sidelobe levels over the required bandwidth. It is especially important that the feed horns preserve the polarisation orientation of the incoming fields. We have used an accurate mode-matching model to design such feed horns. In this paper we present the diffraction analysis of the QUaD front-end optics as well as the electromagnetic design and testing of the QUaD corrugated feeds.