  The evolution of computer-generated holography (CGH) algorithms has prompted
significant improvements in the performances of holographic displays.
Nonetheless, they start to encounter a limited degree of freedom in CGH
optimization and physical constraints stemming from the coherent nature of
holograms. To surpass the physical limitations, we consider polarization as a
new degree of freedom by utilizing a novel optical platform called metasurface.
Polarization-multiplexing metasurfaces enable incoherent-like behavior in
holographic displays due to the mutual incoherence of orthogonal polarization
states. We leverage this unique characteristic of a metasurface by integrating
it into a holographic display and exploiting polarization diversity to bring an
additional degree of freedom for CGH algorithms. To minimize the speckle noise
while maximizing the image quality, we devise a fully differentiable
optimization pipeline by taking into account the metasurface proxy model,
thereby jointly optimizing spatial light modulator phase patterns and geometric
parameters of metasurface nanostructures. We evaluate the metasurface-enabled
depolarized holography through simulations and experiments, demonstrating its
ability to reduce speckle noise and enhance image quality.
