Principal Investigator Mark Schattenburg
Co-investigators George Ricker , Ralf Heilmann
Project Website http://snl.mit.edu/personal_pages/cforest/index.html
Future x-ray astronomy missions will require orders of magnitude improvements in collecting area and resolution. Foils optics are attractive candidates for telescope optics because of the tremendous weight and cost savings which can be achieved compared to traditional monolithic optics. However, substantial improvements in the ability to form and assemble foils to high accuracy will be required. In this new research initiative we are applying a variety of microlithographic technologies to the patterning of assembly structures for the alignment and registration of foil optic components, both reflective and diffractive components.
Silicon Micro-Optical-Mechanical Systems MOMS technology is used to lithographically fabricate silicon microstructures designed to guide and register glass foils into precise three-dimensional shapes with submicron accuracy. Thousands of ~200 µm-thick foils are typically required for an x-ray telescope, each shaped and assembled to form the precise polynomial curves that focus x-rays by grazing-incidence reflection. This microstructure assembly technology is supported by NASA for possible inclusion in the Constellation X telescope.
Plasma micromachining is used to lithographically fabricate silicon microstructures designed to guide and register silicon and glass foils into precise three-dimensional shapes with sub- micron accuracy. Thousands of 200-400µm-thick foils are typically required in an x-ray telescope, each shaped and assembled to form the precise flats or curves that focus x-rays by grazing- incidence reflection.
A prototype flight mirror structure based on these principles has been built and tested. Test results show that glass sheets are assembled to an accuracy of ~1 micron, corresponding to an angle error of ~1 arc-second. This accuracy exceeds previous foil assembly methods by a factor of ~100. The microstructure technology is being supported by NASA as the baseline technology for assembling the optics in the Constellation X telescope.
Recent effort seeks to improve the accuracy of the microcombs from the current level of ~200 nm to under 20 nm. At the improved level it may be possible to achieve diffraction-limited x-ray imaging, which can potentially improve the accuracy of telescopes by over 1000X.