wiregrid

Wiregrid refers to a periodic structure of parallel conductive wires, either freestanding or on a substrate. In optics, infrared, and terahertz technology, wire grids are used as polarization elements and, in radio-frequency engineering, as shielding meshes or components of frequency-selective surfaces.

The grid interacts with light depending on polarization. The electric field component parallel to the wires excites currents and is largely reflected, while the component perpendicular to the wires passes through the gaps with relatively low attenuation. When the wire spacing and diameter are smaller than the wavelength, the grid acts as a high-extinction polarizer, preferentially transmitting one polarization while blocking the other.

Manufacture typically uses metals such as aluminum or gold, formed as a dense array of lines on a dielectric substrate or as a freestanding mesh. Feature sizes control the operating band and polarization discrimination: visible and near-infrared grids have micrometer-scale lines; mid- to far-infrared and THz grids use larger spacings.

Applications include wire-grid polarizers for spectroscopy, astronomy, and imaging; polarization beam splitters in optical systems; and frequency-selective surfaces in RF and microwave engineering. They offer broadband performance and simple fabrication, especially for large apertures, but can suffer from angle sensitivity and mechanical fragility.

Overall, wire grids are a versatile tool in polarization control and electromagnetic design, with design choices driven by wavelength, incidence angle, and mechanical considerations.

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