Detection of arbitrary vortex beams using computer-generated holograms printed on azo-carbazole polymer film

Optical vortices, carried by light beams, are of significant interest due to their intrinsic properties, such as orbital angular momentum and unbounded topological charge, making them valuable for numerous applications. However, conventional methods for generating and detecting these beams often rely on bulky optical setups or complex material fabrication. In this paper, we present a simple and efficient approach for the simultaneous detection of multiple vortex beams. By digitally printing computer-generated holograms on an azo-carbazole polymer film, we generate multiple collinearly superposed optical vortex beams of arbitrary topological charge. Then, we detect the individual topological charges from the superposed beam by employing a second computer-generated hologram. The second hologram diffracts each individual vortex beam to a pre-defined spatial position, and the individual topological charges can be determined by detecting these positions. We show the simultaneous detection of up to three vortex beams using a straightforward and compact arrangement. This technique offers an accessible solution for potential use in optical encryption, storage, and communication technologies.