High-Resolution Imaging of Laser-Produced Plasmas at a Wavelength of 130Å using a Normal Incidence Multilayer-Mirror Microscope

Abstract

Laser-produced plasmas were recently imaged at a wavelength of 44 Å using a spherical multilayer-coated mirror operating near normal incidence, and emission features were recorded with a spatial resolution of 40 μm.1 In order to produce images with better resolution, we have developed a microscope consisting of two spherical mirrors in a Cassegrain-type optical configuration. Spherical optical figure was chosen because of the demonstrated low surface roughness and high optical figure accuracy of previously fabricated mirrors. The spherical aberrations of the concave primary mirror and the convex secondary mirror tend to cancel, and the radii of curvature of the two mirrors and the mirror separation were chosen to minimize the overall spherical aberration of the optical system.