Cady Eric
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.
Opt Express. 2012 Jul 2;20(14):15196-208. doi: 10.1364/OE.20.015196.
An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly model these effects. We present a fast method for the calculation of electric fields following an occulter, based on the concept of the boundary diffraction wave: the 2D structure of the occulter is reduced to a 1D edge integral which directly incorporates the occulter shape, and which can be easily adjusted to include changes in occulter position and shape, as well as the effects of sources-such as exoplanets-which arrive off-axis to the occulter. The structure of a typical implementation of the algorithm is included.
遮光板是一种大型衍射屏，可与望远镜配合使用，对太阳系外行星进行成像。其边缘的形状设计旨在将遮光板后方区域的衍射光减至最少，望远镜可置于这片暗区，以便在去除星光的情况下观测太阳系外系统。遮光板的位置、方向和形状误差会使额外光线衍射进入该区域，而对遮光板系统进行建模面临的一项挑战是准确且快速地对这些效应进行建模。我们基于边界衍射波的概念，提出一种计算遮光板后方电场的快速方法：遮光板的二维结构简化为一维边缘积分，该积分直接纳入了遮光板的形状，并且可以轻松调整以纳入遮光板位置和形状的变化，以及诸如系外行星等离轴到达遮光板的光源的影响。文中还包含了该算法典型实现方式的结构。
