Proximity Glare Suppression using Carbon Nanotubes

In Phase I we demonstrated each aspect required for design and fabrication of Lyot Stops and Apodization Masks for use in a coronagraphic instrument and delivered working components to collaborators at NASA and the Space Telescope Science Institute for evaluation. The technical achievements included: 1) first high quality mirror with carbon nanotubes 2) First nanotubes grown on metallic coatings 3) Dark patterned carbon nanotubes with micron-scaled features. During Phase II we will work with the NASA and STScI collaborators to determine how to improve these components and deliver second generation components to extend the performance of the STScI test bed in support of implementation on future NASA missions such as HABEX or UVOIRS. In addition we will work with NASA collaborators to design and fabricate carbon nanotube coated Lyot Stops for the Visible Nulling Coronagraph (VNC) test bed, also of key importance to the decadal missions referenced above. Lastly, we plan to collaborate with the LISA telescope team at NASA GSFC to design and fabricate a carbon nanotube apodization mask on a powered secondary mirror that could be used in single crystal silicon telescope as a pathfinder for LISA. One of the technical goals of Phase II are to pattern more complex Lyot Stop geometries while maintaining geometrical accuracy through the nanotube growth process. Further optimization of the apodization masks for coronagrahic use include: 1) increasing the metallic coating reflectance to near ideal 2) optimization of the nanotube darkness on the metallic coatings 3) greyscale patterning of carbon nanotubes and medium reflectance coatings on the mirrors to achieve enhanced diffraction suppression. For the LISA telescope diffraction spoiler application we will demonstrate patterning and growth of carbon nanotubes at the micron scale which when combined with metallic nanostructures can provide enhanced field suppression; another enabling technology to NASA missions.