Active metasurfaces in space and time

Electro-optically tunable active metasurfaces that enable dynamic modulation of reflection and transmission amplitude, phase, and polarization using resonantly excited materials and phenomena are powerful design elements for meta-imaging and computation. As flat, low-profile optical elements, active metasurfaces have potential serve as cascadable, programmable components in optical meta-imaging systems, such as lens-less cameras and single-photon imaging systems. In this talk, I will discuss metasurfaces with high quality factor, local, resonant elements capable of two-dimensional phase gradient generation, in both passive and active metasurface designs. I will also describe active metasurfaces with both spatial and temporal phase gradients, and an active metasurface as a lens-less imaging system, and compare the characteristics to conventional lens-coupled image sensors.