In recent years, metasurfaces have attracted a lot of interest in miniaturizing existing optical components either through achieving a smaller size or through integrating different functionalities into a single layer of metamaterial atoms. These are mainly due to the current nano-fabrication capability in putting many nanostructures together in storing a huge amount of information about the wavefront to be created from the metasurfaces. One prominent application is hologram displays in very fine resolution. Moreover, different multiplexing techniques have been explored, e.g., through wavelength, to increase the information capacity of metasurface holograms. One of which is to perform polarization multiplexing. Currently, polarization-multiplexed metasurfaces with 3 independent holograms...[ Read more ]

In recent years, metasurfaces have attracted a lot of interest in miniaturizing existing optical components either through achieving a smaller size or through integrating different functionalities into a single layer of metamaterial atoms. These are mainly due to the current nano-fabrication capability in putting many nanostructures together in storing a huge amount of information about the wavefront to be created from the metasurfaces. One prominent application is hologram displays in very fine resolution. Moreover, different multiplexing techniques have been explored, e.g., through wavelength, to increase the information capacity of metasurface holograms. One of which is to perform polarization multiplexing. Currently, polarization-multiplexed metasurfaces with 3 independent holograms have been demonstrated. To further store more information on the metasurface, it will be desired to have 4 independent holograms to fully exploit all the 4 matrix elements of Jones matrix or even more degrees of freedom. In this thesis, I investigate the possibility to incorporate 4 independent holograms using the full capacity of a Jones matrix. I investigated the symmetries of metamaterial structures in providing such Jones matrices. I proposed a metasurface design that only uses 2 tunable degrees of freedom in geometry to produce 4 independent holograms. By developing a modified GS algorithm that applies the phase constraints coming from the designs of metasurfaces directly, one can obtain the required overall metasurface design in obtaining 4 holograms. By using such algorithm, I simulated 2 sets of hologram images, each set of 4 corresponding to the 4 combinations of input and output polarization channels of the Jones matrix. While I have proved the feasibility of 4 independent holograms with clear features, the transmission efficiency can be further improved. My findings revealed the possibility of utilizing all unique polarization channels of a single metasurface. By combining existing holographic techniques, we may be able to improve the information capacity of metasurface holograms through more input and output channels such as orbital angular momenta.