标题： X射线和伽马射线天文学中的菲涅尔透镜 显示英文标题

标题： Fresnel lenses for X-ray and Gamma-ray Astronomy

摘要： 相位菲涅耳透镜具有与波带板相同的成像特性，但可以将所有入射功率集中到主焦点上，从而将最大理论效率从 11% 提高到接近 100%。 对于 X 射线，特别是伽马射线，大型、衍射受限的相位菲涅耳透镜可以相对容易地制造。 焦距非常长——例如可达一百万公里。 然而，图像相应的高“板尺度”意味着直径几米的衍射受限伽马射线透镜所能实现的超高（亚微弧秒）角分辨率可以通过具有毫米空间分辨率的探测器加以利用。 本文回顾了此类系统在超高角分辨率天文学中的潜力，以及为了某些其他研究所需灵敏度提升所具备的优势，并讨论了其相对于替代方法的优缺点。 我们报告了计划中的缩小规模的“原理验证测试”，并研究了在双航天器任务中实施菲涅耳望远镜的可能性，两艘航天器相隔一百万公里，分别携带透镜和探测器。 这种望远镜能够分辨出超大质量黑洞事件视界的辐射，并且具有足够的灵敏度来探测来自遥远超新星的伽马射线谱线。 我们展示了衍射/折射光学如何在填充孔径透镜和宽带干涉阵列之间产生一系列可能的系统设计。 显示英文摘要

摘要： Phase Fresnel lenses have the same imaging properties as zone plates, but with the possibility of concentrating all of the incident power into the primary focus, increasing the maximum theoretical efficiency from 11% to close to 100%. For X-rays, and in particular for gamma-rays, large, diffraction-limited phase Fresnel lenses can be made relatively easily. The focal length is very long - for example up to a million kms. However, the correspondingly high `plate-scale' of the image means that the ultra-high (sub-micro-arc-second) angular resolution possible with a diffraction limited gamma-ray lens a few metres in diameter can be exploited with detectors having \~mm spatial resolution. The potential of such systems for ultra-high angular resolution astronomy, and for attaining the sensitivity improvements desperately needed for certain other studies, are reviewed and the advantages and disadvantages vis-a-vis alternative approaches are discussed. We report on reduced-scale 'proof-of-principle tests' which are planned and on mission studies of the implementation of a Fresnel telescope on a space mission with lens and detector on two spacecraft separated by one million km. Such a telescope would be capable of resolving emission from super-massive black holes on the scale of their event horizons and would have the sensitivity necessary to detect gamma-ray lines from distant supernovae. We show how diffractive/refractive optics leads to a continuum of possible system designs between filled aperture lenses and wideband interferometric arrays.