[Under construction]2014 AFOSR MURIActive Metasurfaces for Advanced Wavefront Engineering and WaveguidingPO: Dr. Gernot Pomrenke, Optoelectronics and PhotonicsPI: Dr. Frederico Capasso, HarvardWebsite: TBD
Our goal is a coherent effort to demonstrate the major advantages of active metasurfaces. The team will focus on all the aspects: fundamental physics, materials building blocks; device design; meta-surface platforms; quantum meta-surfaces and active meta-surfaces with the goal of demonstrating proof of concept functionalities for the latter such as new spatial light modulators and spatial guided light modulators. The exploration of new physics will focus on: the connection between active metasurface design and the creation and control of surface polaritons and reflected/transmitted beams; the physics of metasurface components such as optical antennas and dielectric resonators, including mechanisms for reconfigurability and tuning; the interaction between quantum emitters and metasurfaces as well as nonlinear metasurfaces for broadband frequency conversion. On the materials side the focus will be on compounds such as transparent conductive oxides, transition metal nitrides, phase change materials and graphene, which offer reduced optical losses and new functionalities such as active tuning of the optical properties by external stimuli. The device effort will focus on new nanoscale building blocks for flat photonics such as tunable/reconfigurable antennas/resonators enabled by the interaction of light with metasurfaces. Such building blocks can be configured into metasurface platforms (Metatronics), described by equivalent optical circuits. These large area multi-layered metasurfaces will incorporate active and nonlinear optical building blocks. By leveraging on in-depth studies of the physics of metasurfaces and metadevices, the team aims to ultimately demonstrate: (a) prototype reflectarrays and transmit arrays in selected spectral regions from the visible to the mid-infrared (mid-IR) for dynamic wavefront control and beam steering; (b) broadband, small-footprint planar photonic devices that integrate optical waveguides into metasurfaces designed for phase matching between waveguide modes; these will include mode converters, polarization rotators, optical diodes and isolators, and on-chip nonlinear optical components. Devices for wavefront control have many DoD applications including range-finding, LIDAR, target designation / illumination and beam steering. Our program will lay the foundations for major advances in active meta-surfaces that will overcome the limitations of weight footprint, speed and movable parts of conventional devices such as spatial light modulators.