Cho Seong Yong, Ono Masaru, Yoshida Hiroyuki, Ozaki Masanori
Division of Electrical, Electronic and Information Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
Sci Rep. 2020 May 18;10(1):8201. doi: 10.1038/s41598-020-65102-0.
Various approaches are being pursued to realize compact optical elements with the ability to manipulate light, but it is difficult to simultaneously achieve high reflectivity and the ability to see through the element. Here, we present a reflective computer-generated hologram that is completely transparent in the visible, based on the Berry (geometric) phase in a self-organizing Bragg reflector. The Bragg reflector has a helical dielectric tensor distribution with the phase information imprinted in the distribution of the optic axis on the substrate. The structure possesses only a single Fourier component and high-order reflections are suppressed; thus, the device appears completely transparent by setting the main reflection band outside the visible range for all angles of incidence accessible by ambient light. On the other hand, the encoded phase information can be played back using visible light by increasing the accessible incidence angle, which we demonstrate experimentally by (i) attaching a coupling prism, and (ii) integrating the device in a waveguide. Bragg-Berry reflectors thus enable a new route to realize advanced optical elements with no apparent reflection in the visible region.
人们正在探索各种方法来实现具有光操纵能力的紧凑型光学元件，但很难同时实现高反射率和元件的透见能力。在此，我们展示了一种基于自组织布拉格反射器中贝里（几何）相位的反射式计算机生成全息图，它在可见光范围内是完全透明的。布拉格反射器具有螺旋介电张量分布，相位信息印刻在基板上光轴的分布中。该结构仅具有单个傅里叶分量，并且高阶反射受到抑制；因此，通过将主反射带设置在环境光可及的所有入射角的可见光范围之外，该器件看起来是完全透明的。另一方面，通过增加可及入射角，可以使用可见光回放编码的相位信息，我们通过（i）连接一个耦合棱镜和（ii）将该器件集成在波导中来进行实验演示。因此，布拉格 - 贝里反射器为实现可见光区域无明显反射的先进光学元件开辟了一条新途径。
