Multiple-Beam Power Combining Using Space-Time Metasurfaces

In this talk, we will present a new concept of space-time power combiners which allow perfect power concentration of plane waves from multiple input directions to a single wave propagating into the desired output direction. Such functionality can be realized in metasurfaces with travelling-wave modulations of the surface impedance. The spatiotemporal modulation imparts different spatial and temporal momenta on the incident beams, such that their reflected beams are spatially collimated and their powers are incoherently summed. The proposed technique has very important applications in unidirectional guiding of electromagnetic signals among multiple routes, as well as in high-power laser technologies.