Programmable metasurfaces: from reconfigurable wavefront to quantum algorithms

Programmability in materials science enables complex functions to be achieved in a controllable manner, either dynamically or statically. In metamaterials research, we are witnessing a surge in this area, particularly in reconfigurability and the dynamic or time-varying tunability of constitutive parameters. This has opened the door to new physics, with applications in holography, imaging, and information processing. In this talk, I will demonstrate two approaches to achieve programmable metasurfaces in the microwave and optical regimes. First, I will present a programmable microwave metasurface that generates electromagnetic fields with time-varying wavefronts. These fields are observed using a two-probe field mapping method, and we introduce a twisting degree of freedom within the time-varying orbital angular momentum. In the second approach, we combine a spatial light modulator with a lens-array metasurface to implement unitary matrix operations, showcasing quantum algorithms with both classical and quantum light. We will also discuss how quantum holograms can be generated from polarization entangled photon pairs using the same approach.