Fig. 3: Superposition of different beam profiles of the spin-decoupled holographic VCSEL, of which the polarization selectivity of each channel can be used for encryption purpose.

In this example, two sets of meta-atoms with different dimensions were employed to construct metasurfaces with relatively high efficiency (Device A) and low efficiency (Device B and Device C). Meanwhile, a broad diverging beam coming from the uncontrolled co-polarization channel was aligned with the spin-decoupled CPs beams to block the holographic images (a). Then, the divergent co-polarization beam spot can be removed from the holographic images with a polarizer, revealing the hidden information (b). Each spin state channel carrying the holographic information can be further selectively concealed by proper CP filtering, taking advantages of their orthogonality (c, d).