[I have been fascinated by the theory of Orbital Angular Momentum (OAM) since I first read about it in the mid 1990s in a UK science publication. I believe that OAM may have some unique applications in RF signaling especially for new multi-spectral coding techniques and medical diagnostic and imaging applications.
Here is an excellent paper that describes the theory behind RF OAM and its many potential applications. I think RF OAM will have a huge impact in terms of new wireless, imaging and diagnostic applications. For more information please see my blog on the subject http://orbitalangularmomentum.blogspot.com/ --BSA]
Radio beam vorticity and orbital angular momentum
The experimental veriﬁcation of vorticity and OAM in radio means that a new frequency range has become available for fundamental as well as applied OAM-based experiments in disciplines ranging from relativistic astrophysics and nanotechnology and biology, to wireless communication with high spectral efﬁciency both classically and quantum mechanically. It also opens for the development of new radio and radar probing techniques, including spiral imaging. It should also be emphasized that certain physical effects and observables associated with electromagnetic OAM, for instance electromagnetic torque, are stronger for lower frequencies than for higher
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