High resolution imaging with multilayer telescopes: resolution performance of the MSSTA II telescopes

Abstract

The Multi-Spectral Solar Telescope Array (MSSTA) is a sounding rocket-borne observatory composed of a set of normalincidence multilayer-coated telescopes that obtained selected bandpass spectroheliograms (44A-1550A) of the Solar atmosphere. These spectroheliograms were recorded on specially fabricated XUV and FUV 70mm Kodak film. Rocket launches of this instrument payload took place in 1991 (MSSTA 1) and 1994 (MSSTA II) at the White Sands Missile Test Range in New Mexico, sponsored by the NASA sounding rocket experiment program. Immediately prior to the 1994 launch, visible light focusing tests of each telescope were performed in-situ using a 195 1 Standard Air Force High Resolution Testtarget, to measure optical resolution performance. We determined that the MSSTA II telescopes performed at diffractionlimited resolutions down to 0.70 arc-second at visible wavelengths. Based on these measurements, we calculated an upperbound to the focusing errors that incorporate the sum of all uncorrelated system resolution errors that affect resolution performance. Coupling these upper-bound estimates with the in-band diffraction limits, surface scattering errors and payload pointing jitter, we demonstrate that eleven of nineteen MSSTA II telescopeshaving negligible figures of focus errors in comparison to the corresponding visible diffraction limitsperformed at sub arc-second resolution at their operational FUV/EUV/XUV wavelengths during flight. We estimate the in-band performance down to 0.14 0.08 second of arc.

Active multilayer mirrors for reflectance tuning at extreme ultraviolet (EUV) wavelengths

“…MLMs find applications in astronomy [1,2], microscopy [3,4], spectroscopy [5], lasers [6] and next generation EUV lithography (EUVL) systems [7], the latter being the main driving force of the field. MLMs for EUVL systems are fabricated by depositing many pairs of Mo and Si layers such that the Bragg condition is satisfied at normal incidence for a wavelength of 13.5 nm [8].…”