Plane spiral orbital angular momentum electromagnetic wave

A new form of the orbital angular momentum (OAM) carried electromagnetic wave termed as plane spiral OAM (PSOAM) electromagnetic wave is proposed for the first time in this paper. This electromagnetic wave possesses the fundamental characters of the OAM-carrying waves, i.e. a spiral phase distribution, yet propagates along the transverse direction. Hence the phase singularity of this wave is in the radiation source itself, which can avoid the wide "dark zone" derived problems in the long distance transmission. The PSOAM electromagnetic waves with different OAM modes can be easily multiplexed as no divergence exists. Owing to the unique wave beam characteristics, some potential applications in wireless communication and electromagnetic sensing are preliminarily discussed.