Edge extraction using a time-varying vortex beam in incoherent digital holography

Edge extraction using a time-varying vortex beam (TV-VB) is demonstrated in optical scanning holography (OSH) operating in an incoherent mode. OSH is a two-pupil heterodyne scanning optical system. We propose that one of the pupil functions used is a delta function and the other pupil function is a spiral phase plate (SPP). The interference of these pupils creates a TV-VB to scan over an object to record the edge-only information of an object holographically. We also find that a reconstructed edge with better contrast is achieved by translating the SPP away from the pupil plane. Experimental results are compared with computer simulations and found to be in good agreement.