Mitigation of lateral misalignment in the optical set-up for the generation of perfect vortex beam by the radial shearing self-interferometric (RSSI) technique

Abstract

Traditionally, interference patterns play an important role in determining the sign and magnitude of the orbital angular momentum (OAM) of the vortex beam. However, we demonstrate the importance of interference patterns in the identification and mitigation of lateral misalignment in the optical set-up, studied through the Radial Shearing Self-Interferometric (RSSI) technique. A splitting of the interference pattern of the perfect vortex beam (PVB) was observed with the introduction of lateral misalignment. These interference patterns proved to be instrumental in the identification of minute misalignment (micron level) in the optical set-up. The splitting in the interference patterns has been detected through image processing and an algorithm for automating the mitigation process has been proposed. The technique could prove to be a step towards self-aligning optical set-ups.