Electromagnetic metasurface

An electromagnetic metasurface refers to a kind of artificial sheet material with sub-wavelength thickness. Metasurfaces can be either structured or unstructured with subwavelength-scaled patterns in the horizontal dimensions.

In electromagnetic theory, metasurfaces modulate the behaviors of electromagnetic waves through specific boundary conditions rather than constitutive parameters in three-dimensional (3D) space, which is commonly exploited in natural materials and metamaterials. Metasurfaces may also refer to the two-dimensional counterparts of metamaterials. There are also 2.5D metasurfaces that involve the third dimension as additional degree of freedom for tailoring their functionality.