标题： 双级Lyot日冕仪与极大型望远镜的优化渐变光栏 显示英文标题

标题： Double stage Lyot coronagraph with the apodized reticulated stop for extremely large telescope

摘要： 极大望远镜（ELT）的科学驱动之一是成像和光谱观测距离母星最近可达20毫弧秒的太阳系外行星。 这项应用需要精心设计的高对比度成像仪器。 针对直径达8米的整体式望远镜，已经开发出几种工作级的日冕观测概念。 然而，关于这些系统的性能得出的结论不能直接应用于直径30-100米的望远镜。 现有方案需要重新考虑，以考虑到分块表面的具体特性。 我们从经典的劳埃特日冕仪系统开始这项工作。 我们表明，虽然望远镜直径增加对高对比度范围科学是一个优势，但分块设置限制了日冕仪的性能。 从分段间隙处的衍射设定了可实现的星光消光的下限。 虽然在劳埃特平面屏蔽明亮的分段间隙有助于提高对比度，但这并不能完全解决问题：衍射光的高频成分仍然存在。 我们建议使用劳埃特光阑，它作用于间隙内的光线，以便在劳埃特平面产生均匀照明。 我们显示，在衍射极限状态下和完美相位情况下，这种类型的日冕仪能够达到足够的星光消光。 显示英文摘要

摘要： One of the science drivers for the extremely large telescope (ELT) is imaging and spectroscopy of exo-solar planets located as close as 20mas to their parent star. The application requires a well thought-out design of the high contrast imaging instrumentation. Several working coronagraphic concepts have already been developed for the monolithic telescope with the diameter up to 8 meter. Nevertheless the conclusions made about the performance of these systems cannot be applied directly to the telescope of the diameter 30-100m. The existing schemes are needed to be reconsidered taking into account the specific characteristics of a segmented surface. We start this work with the classical system ? Lyot coronagraph. We show that while the increase in telescope diameter is an advantage for the high contrast range science, the segmentation sets a limit on the performance of the coronagraph. Diffraction from intersegment gaps sets a floor to the achievable extinction of the starlight. Masking out the bright segment gaps in the Lyot plane although helps increasing the contrast, does not solve completely the problem: the high spatial frequency component of the diffractive light remains. We suggest using the Lyot stop which acts on the light within gaps in order to produce the uniform illumination in the Lyot plane. We show that for the diffraction limit regime and a perfect phasing this type of coronagraph achieves a sufficient star light extinction.