Generation and Switching/Routing of Optical Ferris Wheel using a π-shifted Sagnac Interferometer

Optical Ferris wheel/petal beams can be generated by interference of two beams with opposite vorticity/orbital angular momentum (OAM). We present a simple scheme employing a Sagnac interferometer containing a spiral phase plate to generate such beams. A half wave plate introduced into the SI can switch the intensity pattern between the two outputs and rotate the petal beams. This can find applications in optical trapping, optical information transmission and processing/signal multiplexing/de-multiplexing when using beams with high vorticity/OAM.