Dissertation Defense: Ryker Eads, "Design and Metrology of Optics for Telescopes and Sunlight Concentration"

    Tuesday, February 9, 2021 - 3:30pm

    Attend on Zoom

    Password: 049890


    The principles of optical and metrology design form the foundation for technologies in many areas. Of interest to this dissertation are the areas of solar energy and telescopes. For solar energy, low quality (~1 mrad) solar disk images are formed for the purposes of photovoltaic or heat energy production. For space and ground telescopes, high quality (0.1-1.0 μrad) stellar images can be formed, especially over wide fields where phenomena such as dark energy can be further studied. There are 3-4 magnitudes of difference in precision between solar energy and telescopes, and yet similar optical and metrology design principles are applicable.

    Concentrated Solar Power (CSP) is of special interest. Industry standards involve usage of tens of thousands of heliostats acting as pseudo-pinhole cameras to focus sunlight on a central "power tower" at ~1000X solar concentration. Concave focusing heliostats are of limited value, they suffer from spillage of sunlight around the tower receiver due to changing astigmatic aberrations as the sun angle changes. We have designed and built a prototype that uses active bending astigmatic modes in a 1.6 m2 heliostat mirror, demonstrating sharp disk images of the Sun formed from 0 degree angle of incidence to >70 degree angle of incidence with >90% ensquared energy into an area little larger than the disc image. With ~10X concentration only hundreds of heliostats are needed to achieve ~1000X. 

    Several telescope designs are presented, including a ground telescope with 10,000 m2 of area that can achieve 300,000X spectroscopic resolution for the oxygen band. This makes possible the search for life on exoplanets. Another design is presented that pushes resolution and field of view to the very limits of a 20-m space telescope with ~0.01 arcsecond resolution (at 1 μm wavelength) and a 1-degree field of view.