Width of a wire grid polarizer

[deep838]

Why is it that the width of a wire grid polarizer has to be less than the wavelength of the wave which I want to polarize? What would happen if the width was a little bit more?

 

[Andy Resnick]

If I understand you correctly, the spacing between the wires of a wire polarizer need to be less than a wavelength to minimize light scattering- you want the field to respond to 'macroscopic' (spatially averaged) properties of the device, not the microscopic structure, similar to how visible polarizers use long-chain molecules to act as an anisotropic medium.

 

[deep838]

If I understand you correctly, the spacing between the wires of a wire polarizer need to be less than a wavelength to minimize light scattering.

how does that reduce the scattering of light.?

 

[Andy Resnick]

The polarizer would then appear to be a homogeneous object, not an array of discrete scatterers.