EUV Photon Sieves for Milli-Arcsecond Imaging of the Solar Corona

A photon sieve is a variant of a Fresnel zone plate that can achieve diffraction-limited angular resolution in the extreme ultraviolet (EUV). Existing EUV instruments such as SDO/AIA and Hi-C are reflecting telescopes, and fall short by an order of magnitude or more from achieving the diffraction limit, because the mirrors cannot be figured to the requisite accuracy. Photon sieves offer the ability to obtain diffraction-limited EUV images using imaging elements with greatly relaxed manufacturing tolerances: sub-micron as opposed to the sub-nanometer requirements for conventional telescopes. Furthermore, sieves can isolate strong EUV emission lines for a wide range of temperatures in the solar atmosphere, including eruptive events. The unprecedented resolution achieved will allow us to observe individual dissipation regions in the solar corona and at last understand how the corona is powered. Understanding the heating of coronal plasmas and solar eruptive events are at the heart of NASA's strategic goal to Understand the Sun and its interactions with Earth and the solar system. Therefore, we propose to manufacture large-aperture photon sieves, demonstrate diffraction-limited EUV imaging in the laboratory, and perform environmental testing of the sieves for space flight. More »