Evaluation of the Laguerre-Gaussian mode purity produced by three-dimensional-printed microwave spiral phase plates

pictorial representation of the radio signal passing through an spp with a staircase design

Professor Patrick Grant, Dr Dmitry Isakov and Yingwei Wu worked with Oxford's Department of Engineering and Warwick University to improve the manufacture of dielectric spiral phase plates (SPPs), which generate electromagnetic waves with helical wavefronts.


Three types of SPPs were additively manufactured using material extrusion and polyjet fabrication methods.  The orbibal angular momentum mode characteristics of the transformed helical microwaves as a function of the SPP geometrical features were investigated experimentally in the 12-18 GHz frequency range.


The SPPs were further combined with an additively manufactured dielectric lens that provided a marked improvement in orbital angular momentum mode purity.


The multiplexing and de-multiplexing of two orbital angular momentum modes were demonstrated successfully using an optimimum SPP geometry and arrangement.


You can read the full paper in Volume 7 of Royal Society Open Science.