Detection of double orbital angular momentum modes in monochromic dynamic bi-orbital angular momentum multiplexing by ptychography

Coherent diffractive ptychographic imaging via a modified multi-state ptychographic algorithm can be used to simultaneously detect double orbital angular momentum (OAM) modes in monochromatic bi-OAM-mode multiplexing. The wavefronts for individual vortex beams modulated by two-dimensional amplitude and temporal pulses and mixed together can be reconstructed independently. In contrast to most other OAM detection methods, this approach solves for the OAM detection in a monochromatic dynamic multi-OAM beam and can be applied as an early step in OAM mode demultiplexing.