Javed Isma, Kim Joohoon, Naveed Muhammad Ashar, Oh Dong Kyo, Jeon Dongmin, Kim Inki, Zubair Muhammad, Massoud Yehia, Mehmood Muhammad Qasim, Rho Junsuk
MicroNano Lab, Electrical Engineering Department, Information Technology University (ITU) of the Punjab, Lahore 54600, Pakistan.
Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
ACS Appl Mater Interfaces. 2022 Aug 10;14(31):36019-36026. doi: 10.1021/acsami.2c07960. Epub 2022 Aug 1.
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.
超表面全息术的巨大潜力有望为成像、芯片集成增强/虚拟现实（AR/VR）技术和平板光学显示器带来革命性进展。组成元素几何形状的选择限制了许多通过偏振无关光学响应实现的潜在应用。常用超原子的能力和自由度有限，限制了打破偏振不敏感和带宽之间传统权衡的设计灵活性。在此，我们提出一种基于几何相位的新颖设计策略来打破这种传统权衡。所提出的策略通过简化的设计流程确保实现宽带偏振不敏感。在不同的入射偏振条件下，通过调整几何相位工程的相位延迟自由度，可以实现相同的输出波前操控。为了验证概念，我们用优化的与互补金属氧化物半导体（CMOS）兼容的氢化非晶硅（a-Si:H）材料制作了一个超全息图器件。该超全息图器件在白光入射的不同偏振场景下，能够以高图像保真度和效率再现所需的全息图。由于设计策略简单、计算成本低且易于制作，所提出的技术有望成为实现偏振不敏感超全息图器件的理想选择。
