Symmetric spin–orbit interaction (SOI)‐based approaches apply a practical limit on helicity multiplexed metaoptics, i.e., center symmetric information encoding. Contrarily, asymmetric SOI's based on the combination of geometric and propagation phase‐delay approaches can effectively address such limitations for multifunctional multiplexed metaoptics on the cost of design complexities. In this paper, a simple asymmetric SOI‐based technique is realized for multifunctional metaoptics, employing only a single unit cell, breaking the conventional tradeoff between design complexity and efficient asymmetric transmission efficiency. The design approach depends on geometric phase alone, which eases the fabrication challenges and decreases the computational cost associated with previous asymmetric SOI‐based metaoptics. Furthermore, this study utilizes a new, low‐cost CMOS‐compatible material to optimize the proposed single unit cell for low loss and high transmission efficiency over the complete visible domain. On‐axis and off‐axis holographic metasurfaces are designed and integrated with pressure‐sensitive liquid crystal cells to demonstrate actively tunable metaholography with no limitation of center symmetric information encoding. The simple design technique, cost‐effective fabrication, and finger touch‐enabled holographic output switching make this integrated setup a potential candidate for many applications such as smart safety labeling, motion or touch recognition, and interactive displays for impact monitoring of precious artworks and products.

The remarkable potential of metasurface holography promises revolutionary advancements for imaging, chip-integrated augmented/virtual reality (AR/VR) technology, and flat optical displays. The choice of constituent element geometry constrains many potential applications purveyed through polarization-independent optical response. The limited capabilities and degree of freedoms in commonly used meta-atoms restrict the design flexibility to break the conventional trade-off between polarization-insensitivity and bandwidth. Here, we propose a geometric phase-enabled novel design strategy to break this conventional trade-off. The proposed strategy ensures the realization of broad-band polarization-insensitivity through a simplified design procedure. An identical output wavefront manipulation is achieved by adjusting the phase delay freedom of geometric phase engineering under different incident polarization conditions. For proof of concept, a metahologram device is fabricated by an optimized complementary metal–oxide–semiconductor (CMOS)-compatible material of hydrogenated amorphous silicon (a-Si:H). This metahologram device reproduces the required hologram with high image fidelity and efficiency under different polarization scenarios of white light incidence. Due to the simple design strategy, low computational cost, and easy fabrication, the proposed technique can be an excellent candidate for realizing polarization-insensitive metahologram devices.

Due to the considerable potential of ultra-compact and highly integrated meta-optics, multi-functional metasurfaces have attracted great attention.

Highly non-diffracting bessel beams have gathered an excessive amount of significance due to their several applications ranging from optical communication, displays to trapping and manipulation. Array of bessel beams with multiple orders is generated by utilizing geometric metasurfaces to have full phase control over optical properties of light. In prior works, Bessel beams are realized with optical metasurfaces of titanium dioxide (TiO2) and gallium nitride (GaN) but they have bottlenecks in terms of complex and expensive fabrication. Here, in this manuscript we have represented single layer optical metasurface based on gallium phosphide (GaP) for Bessel beam generation. The proposed metasurface has high transmission efficiency in visible regime and capable of producing four bessel beams of arbitrary orders without the accumulation of extra complexities in conventional nanorectangular pillar geometry. Due to property of orbital angular momentum, these arbitrary order bessel beams have high capacity for data storage. Thus, they provide an appropriate plateform for numerous interesting phenomena of data encryption and information storage.

No abstract