2023-05-08 コロンビア大学
◆これは、振幅、位相、偏光楕円率、偏光方向など、光学的自由度の4つすべてを制御する初めての装置であり、光透過性が高く、薄く、光子集積回路（PIC）と互換性があるため、光学表示、LIDAR、光学通信、量子光学などの分野で利用できる。また、両分野をハイブリッドにすることで、新しい応用に対応する方法を提供するという。
＜関連情報＞
- https://www.engineering.columbia.edu/news/leaky-wave-metasurfaces-interface-free-space-integrated-optical-systems
- https://www.nature.com/articles/s41565-023-01360-z
集積フォトニクスのための漏洩波メタサーフェス Leaky-wave metasurfaces for integrated photonics
Heqing Huang,Adam C. Overvig,Yuan Xu,Stephanie C. Malek,Cheng-Chia Tsai,Andrea Alù & Nanfang Yu
Nature Nanotechnology Published:08 May 2023
DOI:https://doi.org/10.1038/s41565-023-01360-z
Abstract
Metasurfaces have been rapidly advancing our command over the many degrees of freedom of light; however, so far, they have been mostly limited to manipulating light in free space. Metasurfaces integrated on top of guided-wave photonic systems have been explored to control the scattering of light off-chip with enhanced functionalities—namely, the point-by-point manipulation of amplitude, phase or polarization. However, these efforts have so far been limited to controlling one or two optical degrees of freedom at best, as well as device configurations much more complex compared with conventional grating couplers. Here we introduce leaky-wave metasurfaces, which are based on symmetry-broken photonic crystal slabs that support quasi-bound states in the continuum. This platform has a compact form factor equivalent to the one of grating couplers, but it provides full command over the amplitude, phase and polarization (four optical degrees of freedom) across large apertures. We present devices for phase and amplitude control at a fixed polarization state, and devices controlling all the four optical degrees of freedom for operation at a wavelength of 1.55 μm. Merging the fields of guided and free-space optics through the hybrid nature of quasi-bound states in the continuum, our leaky-wave metasurfaces may find applications in imaging, communications, augmented reality, quantum optics, LIDAR and integrated photonic systems.
