Radial polarization

In practice, an array of waveplates may be used to provide an approximation to a radially polarized beam.

Called a "Rotated Brewster Angle Polarizer," the latter was first proposed and put into practice (1986) to produce a radially-polarized annular pupil by Guerra [4] at Polaroid Corporation (Polaroid Optical Engineering Dept., Cambridge, Massachusetts) to achieve super-resolution in their Photon Tunneling Microscope.

A metal bi-cone, formed by diamond-turning, was mounted inside a glass cylinder.

[9] It has been shown that a radially polarized beam can be used to increase the information capacity of free space optical communication via mode division multiplexing,[10] and radial polarization can "self-heal" when obstructed.

[12] The relativistic longitudinal electric field component has been proposed as a driver for particle acceleration in free space[13][14] and demonstrated in proof-of-concept experiments.