The large volume of optical systems, such as cameras and near-eye visors in mixed reality systems, often originates from the requirement of having multiple optical elements and thick spherical geometries. In recent years, researchers have made optical elements based on subwavelength diffractive arrays of ‘optical antennas’, commonly known as metasurfaces. These components achieve ultra-thin form factors and leverage well-developed semiconductor nano-fabrication technology for manufacturing. In parallel with the progress in such nano-photonic devices, researchers have also made vast improvements in the field of freeform optics. Freeform optics aims to expand the toolkit of optical elements beyond those exhibiting rotational symmetry, enabling aberration correction and development of advanced imaging techniques.
In our work, we demonstrate how metasurfaces made of dielectric materials can be used for the realization of subwavelength scale freeform optics, with applications in imaging and near-eye visors. I will present some of our recent experimental results on metasurface freeform optics that enable a large depth of focus and a tunable focal length lens. I will show how these metasurfaces can be used to perform full-color imaging exploiting computational imaging techniques . I will also discuss the use of computation to design novel metasurfaces  with applications in optical sensing. Finally, I will describe the design of a metasurface-based near eye visor .
 S. Colburn, A. Zhan, and A. Majumdar, “Metasurface optics for full-color computational imaging,” Science Advances, vol. 4, 2018.
 A. Zhan, T. K. Fryett, S. Colburn, and A. Majumdar, “Inverse design of optical elements based on arrays of dielectric spheres,” Applied Optics, vol. 57, pp. 1437-1446, 2018/02/20 2018.
 C. Hong, S. Colburn, and A. Majumdar, “Flat metaform near-eye visor,” Applied Optics, vol. 56, pp. 8822-8827, 2017/11/01 2017.
Prof. Arka Majumdar is an Assistant Professor in the departments of Electrical and Computer Engineering and Physics at the University of Washington, Seattle. He received his B. Tech. degree from the Indian Institute of Technology, Kharagpur in 2007, where he was honored with the President’s Gold Medal. Majumdar completed his master’s degree (2009) and Ph.D. (2012) in Electrical Engineering at Stanford University. He spent one year at the University of California, Berkeley (2012-13) and also at Intel Labs as a postdoc in Santa Clara, CA (2013-14). His research interests include developing a hybrid integrated nanophotonic platform using emerging material systems for applications in ultra-low power optical information science, imaging, and microscopy. Majumdar is the recipient of the Young Investigator Award from the Air Force Office of Scientific Research (2015), Intel early career faculty award (2015), Alfred P. Sloan research fellowship for physics (2018), and NSF CAREER Award (2019).