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 nylon- made 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 fre- quencies 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.