Design and Characterization of a Dielectric Q-plate for Millimetre-wave Photon Orbital Angular Momentum Applications

We present the design, fabrication and beam pattern characterization of a nylonmade q-plate that generates +/- 2 charged OAM states at millimetre wavelengths. This q-plate is optimized to work around 100 GHz but the same design can be scaled to work at other frequencies in the millimetre-wave range. The simple manufacturing method used here allows a cheap and fast q-plate production. The designed plate can create a point defect on the phase front structure of a fundamental Gaussian beam with the associated optical vortex and annular intensity pattern. The q-plate has been experimentally characterized using a millimetre-wave Vector Network Analyzer and beam scanning test set-up.