Optical interface engineering with on-demand magnetic surface conductivities

Optical interfaces with arbitrary magnetic and electric surface conductivities can enable the design of photonic devices with new functionalities, but practical approaches to date are nonexistent. Regular interfaces, such as those with graphene, are optically interesting due to their tailorable electric surface conductivity. However, their magnetic surface conductivity is negligible since the magnetic response in natural materials is generally weak from the terahertz frequency onward. The quest for artificial magnetic response has recently triggered the development of magnetic metasurfaces that, however, can only provide the interface with a limited value of magnetic surface conductivity. Herein we find that vertical heterostructures based on regular nonmagnetic metasurfaces have a direct correspondence to an optical interface with both magnetic and electric surface conductivities, whose desired values can be structurally engineered. Moreover, we identify several unique photonic and plasmonic responses at optical interfaces with specific magnetic surface conductivities, including a polarization-insensitive Brewster effect and pure magnetic surface waves.