Imaging planets in reflected light, a key focus of future NASA missions and ELTs, requires advanced wavefront control to maintain a deep, temporally correlated null of stellar halo -- i.e. a dark hole -- at just several diffraction beam widths. Using the Ames Coronagraph Experiment testbed, we present the first laboratory tests of Spatial Linear Dark Field Control (LDFC) approaching raw contrasts ($\sim$ 5$\times$10$^{-7}$) and separations (1.5--5.2 $\lambda$/D) needed to image jovian planets around Sun-like stars with space-borne coronagraphs like WFIRST-CGI and image exo-Earths around low-mass stars with future ground-based 30m class telescopes. In four separate experiments and for a range of different perturbations, LDFC largely restores (to within a factor of 1.2--1.7) and maintains a dark hole whose contrast is degraded by phase errors by an order of magnitude. Our implementation of classical speckle nulling requires a factor of 2--5 more iterations and 20--50 DM commands to reach contrasts obtained by spatial LDFC. Our results provide a promising path forward to maintaining dark holes without relying on DM probing and in the low-flux regime, which may improve the duty cycle of high-contrast imaging instruments, increase the temporal correlation of speckles, and thus enhance our ability to image true solar system analogues in the next two decades.

中文翻译：

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用于在反射光下成像系外行星的空间线性暗场控制的实验室演示

在反射光中对行星进行成像，这是未来 NASA 任务和 ELT 的一个关键焦点，需要先进的波前控制，以在几个衍射光束宽度下保持深的、时间相关的恒星晕（即黑洞）。使用 Ames Coronagraph 实验台，我们展示了空间线性暗场控制 (LDFC) 接近原始对比度 ($\sim$ 5$\times$10$^{-7}$) 和分离 (1.5--5.2) 的首次实验室测试$\lambda$/D) 需要使用 WFIRST-CGI 等星载日冕仪对类太阳恒星周围的类木行星进行成像，并使用未来的地面 30m 级望远镜对低质量恒星周围的系外地球进行成像。在四个单独的实验和一系列不同的扰动中，LDFC 大部分恢复（在 1.2--1 的因子内。7) 并保持一个黑洞，其对比度因相位误差而降低一个数量级。我们对经典散斑归零的实现需要 2--5 倍的迭代和 20--50 个 DM 命令才能达到空间 LDFC 获得的对比度。我们的研究结果为在不依赖 DM 探测和低通量状态下维持黑洞提供了一条有希望的途径，这可能会改善高对比度成像仪器的占空比，增加斑点的时间相关性，从而增强我们的能力在接下来的二十年中成像真正的太阳系类似物。