Fig. 2: Algorithm flowchart and experimental optical setup of the discontinuous OAM metasurface holography.

a The algorithm flowchart for the design of four-channel discontinuous OAM metasurface holography. In each channel, the sampled image is multiplied by a 2D Dirac comb function, followed by a modified WGS algorithm to acquire the holographic phase information. The obtained phase is added with the corresponding discontinuous OAM helical phase. The final phase profile is obtained by superimposing all holographic channels, leading to the design of multi-channel OAM holography in a single phase profile. b Experimental setup of the holographic measurement. L1–L4 lens, P polarizer, QWP quarter-wave plate, SLM spatial light modulator, BS beam splitter, CCD charge-coupled device. c SEM image of the fabricated metasurface under tilted view.