Propagation of perfect vortex beam beyond the focal depth

Perfect vortex beam (PVB) has emerged as a promising candidate in the field of optical communication, which is currently limited due to its realization only at the focal depth of Fourier lens. The present letter reports devising of a unique technique for the propagation of PVB beyond this point and has been verified experimentally, inside laboratory, up to a distance of 5 m. The properties of PVBs, observed at the focus of the Fourier lens, were well preserved in the propagated beams. This proposed approach ensures preserving of the invariance of the annular radius of propagating PVBs, carrying different orbital angular momentum, which has emerged as a unique property for their potential application in the fields of communication, particle trapping, and micro-machining.