Generation of mm-Wave Higher Order OAM Modes using Flat Phase Plates

In order to demonstrate high data rate secure transmission using orbital angular momentum (OAM) modulated beams, we have designed flat OAM phase plates. We report generation of orthogonal OAM beams having OAM L = 1-4. These flat phase plates (FPP) are made of high permittivity material of ε ≈ 10.8. An iterative circle packing technique, with circles representing the holes in a dielectric, has been used to design the FPP for each specific OAM mode. Numerical simulations are carried out using a horn excitation on the FPPs to produce the required OAM modulations. Experimental results of OAM beam generation and demodulation to demonstrate high data rate transmission will be presented in the meeting.