For the longest time OAM was associated with optical photonic applications. I have suspected for some time it could be used in RF frequency bands as well. A recent paper discusses this:
"Utilization of Photon OAM in Low Frequency Radio Domain", B. Thide
Even more exciting is the use of RF OAM to probe properties of objects:
Recent digital spiral imaging experiments (Torner et al., Opt.
Express, 13, 873–881, 2005; Molina-Terriza et al., J. Eur. Opt.
Soc., Rapid Publ., 2, 07014, 2007) have demonstrated that
probing with OAM gives a wealth of new information about the
object under study.
