Département Optique Théorique et Appliquée, Office national d’études et de recherches aérospatiales (ONERA), Châtillon BP72 92322, France. jean‑
Opt Lett. 2012 Dec 1;37(23):4808-10. doi: 10.1364/OL.37.004808.
Exoplanet direct imaging is a challenging goal of today's astronomical instrumentation. Several high-contrast imaging instruments dedicated to this task are currently being integrated; they are ultimately limited by the presence of quasi-static speckles in the imaging focal plane. These speckles originate in residual quasi-static optical aberrations, which must be measured and compensated for, typically at a nanometric level. We present a novel focal plane wavefront sensor (WFS) designed for this particular application. It is an extension of the phase diversity technique to coronagraphic imaging. This sensor requires no dedicated hardware and uses only two scientific images differing from a known aberration, which can be conveniently introduced by the adaptive optics subsystem. The aberrations are therefore calibrated all the way down to the scientific camera, without any differential aberrations between the sensor and the scientific camera. We show the potential of this WFS by means of simulations, and we perform a preliminary experimental validation.
系外行星直接成像一直是当今天文仪器的一个挑战性目标。目前，有几个专门用于该任务的高对比度成像仪器正在进行集成；它们最终受到成像焦平面上准静态斑点的限制。这些斑点源于残余的准静态光学像差，必须对其进行测量和补偿，通常要达到纳米级水平。我们提出了一种专为该特定应用而设计的新型焦平面波前传感器 (WFS)。它是相位差分技术在日冕成像中的扩展。这种传感器不需要专用硬件，只使用两幅与已知像差不同的科学图像，自适应光学子系统可以方便地引入这些像差。因此，像差可以一直校准到科学相机，而传感器和科学相机之间没有任何差分像差。我们通过模拟展示了这种 WFS 的潜力，并进行了初步的实验验证。
