Space-time meta-surfaces for light waves

In this project we propose experiments to develop the building blocks of a space-time metasurface for optical waves, based on large and ultrafast modulations of the complex refractive index of indium tin oxide (ITO). Static metasurfaces have been a milestone in how we control light waves by manipulating their phase and amplitude on the wavelength scale. Yet, they are still bounded by Lorentz reciprocity and energy conservation. A dynamical metasurface, whose optical response can be fully controlled at the speed of light through a time-varying refractive index, n(x,t), would not be just a powerful technological element, but would also bring about the rich new physics of non-Hermitian and non-time-reversible optics.