Yoon Gwanho, Lee Dasol, Nam Ki Tae, Rho Junsuk
Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea.
Sci Rep. 2018 Jun 21;8(1):9468. doi: 10.1038/s41598-018-27876-2.
A polarization independent holographic beam splitter that generates equal-intensity beams based on geometric metasurface is demonstrated. Although conventional geometric metasurfaces have the advantages of working over a broad frequency range and having intuitive design principles, geometric metasurfaces have the limitation that they only work for circular polarization. In this work, Fourier holography is used to overcome this limitation. A perfect overlap resulting from the origin-symmetry of the encoded image enables polarization independent operation of geometric metasurfaces. The designed metasurface beam splitter is experimentally demonstrated by using hydrogenated amorphous silicon, and the device performs consistent beam splitting regardless of incident polarizations as well as wavelengths. Our device can be applied to generate equal-intensity beams for entangled photon light sources in quantum optics, and the design approach provides a way to develop ultra-thin broadband polarization independent components for modern optics.
展示了一种基于几何超表面的偏振无关全息分束器，它能产生等强度光束。尽管传统几何超表面具有在宽频率范围内工作以及设计原理直观的优点，但几何超表面存在仅适用于圆偏振的局限性。在这项工作中，利用傅里叶全息术来克服这一局限性。编码图像的原点对称性导致的完美重叠实现了几何超表面的偏振无关操作。通过使用氢化非晶硅对设计的超表面分束器进行了实验验证，该器件无论入射偏振和波长如何，都能实现一致的光束分裂。我们的器件可应用于为量子光学中的纠缠光子光源产生等强度光束，并且该设计方法为现代光学开发超薄宽带偏振无关组件提供了一种途径。
