Flat optical devices based on lithographically patterned sub-wavelength dielectric nano-structures provide precise control over optical wavefronts, and thus promise to revolutionize the field of free-space optics. I discuss our work on high contrast transmitarrays and reflectarrays composed of silicon nano-posts located on top of low index substrates like silica glass or transparent polymers. Complete control of both phase and polarization is achieved at the level of single nano-post, which enables control of the optical wavefront with sub-wavelength spatial resolution. Using this nano-post platform, we demonstrate lenses, waveplates, polarizers, arbitrary beam splitters and holograms. Devices that provide multiple functionalities, like simultaneous polarization beam splitting and focusing are implemented. By embedding the metasurfaces in flexible substrates, conformal optical devices that decouple the geometrical shape and optical function are shown. Multiple flat optical elements are integrated in optical systems such as planar retro-reflectors and Fourier lens systems with applications in ultra-compact imaging systems. Applications in microscopy and the prospects for tunable devices are discussed.
Dr. Andrei Faraon is an Assistant Professor of Applied Physics, Materials Science and Medical Engineering at California Institute of Technology. After earning a B.S. degree in physics with honors in 2004 at California Institute of Technology, he received his M.S. in Electrical Engineering and PhD in Applied Physics both from Stanford University in 2009. At Stanford, Dr. Faraon was involved with seminal experiments on quantum optics using single indium arsenide quantum dots strongly coupled to photonic crystal cavities in gallium arsenide. After earning his PhD, Dr. Faraon spent three years as a postdoctoral fellow at Hewlett Packard Laboratories. At HP he was involved with pioneering experiments on diamond quantum photonic devices coupled to solid-state spins. He demonstrated the first nano-resonators coupled to single nitrogen vacancy centers in mono-crystalline diamond.
Faraon left HP in 2012 to become an Assistant Professor at Caltech. At Caltech, he set up a laboratory specialized in developing nano-photonic technologies for devices that operate close to the fundamental limit of light-matter interaction. He is focused both on fundamental challenges on how to control the interaction between single atoms and single photons using nano-technologies, and on using nano-photonics to build cutting edge devices for bio-imaging, bio-sensing and photo-voltaic energy harvesting. He is the recipient of the NSF CAREER award, the AFOSR young investigator award and the ONR young investigator award.