Graduate Institute of Applied Physics, National Taiwan University , Taipei 10617, Taiwan.
Nano Lett. 2014 Jan 8;14(1):225-30. doi: 10.1021/nl403811d. Epub 2013 Dec 18.
Holograms, the optical devices to reconstruct predesigned images, show many applications in our daily life. However, applications of hologram are still limited by the constituent materials and therefore their working range is trapped at a particular electromagnetic region. In recent years, the metasurfaces, an array of subwavelength antenna with varying sizes, show the abilities to manipulate the phase of incident electromagnetic wave from visible to microwave frequencies. Here, we present a reflective-type and high-efficiency meta-hologram fabricated by metasurface for visible wavelength. Using gold cross nanoantennas as building blocks to construct our meta-hologram devices with thickness ∼ λ/4, the reconstructed images of meta-hologram show polarization-controlled dual images with high contrast, functioning for both coherent and incoherent light sources within a broad spectral range and under a wide range of incidence angles. The flexibility demonstrated here for our meta-hologram paves the road to a wide range of applications related to holographic images at arbitrary electromagnetic wave region.
全息图是一种用于重建预定图像的光学器件，在我们的日常生活中有许多应用。然而，全息图的应用仍然受到组成材料的限制，因此它们的工作范围被限制在特定的电磁区域内。近年来，超表面，一种由不同尺寸的亚波长天线组成的阵列，显示出从可见光到微波频率的操控入射电磁波相位的能力。在这里，我们提出了一种由超表面制造的用于可见光波长的反射式高效元全息图。使用金十字纳米天线作为构建块，用厚度约为 λ/4 的超表面构建元全息图器件，元全息图的重建图像显示出具有高对比度的偏振控制双图像，对相干和非相干光源在宽光谱范围内和宽入射角范围内都有效。这里展示的元全息图的灵活性为在任意电磁波区域实现与全息图像相关的广泛应用铺平了道路。
