Optical metasurfaces, which consist of subwavelength scale meta-atoms, represent a novel platform to manipulate the polarization and phase of light. The optical performance of metasurfaces heavily relies on the quality of nanofabrication. Retrieving the Jones matrix of an imperfect metasurface optical element is highly desirable. We show that this can be realized by decomposing the generalized Jones matrix of a meta-atom into two parallel ones, which correspond to the ideal matrix and a phase retardation. To experimentally verify this concept, we designed and fabricated metasurface polarizers, which consist of geometric phase-controlled dielectric meta-atoms. By scanning the polarization states of the incident and transmitted light, we are able to extract the coefficients of the two parallel matrices of a metasurface polarizer. Based on the results of the Jones matrix decomposition, we also demonstrated polarization image encryption and spin-selective optical holography. The proposed Jones matrix retrieval protocol may have important applications in computational imaging, optical computing, optical communications, and so on.

Optical metasurfaces are currently an important research area all around the world because of their wide application opportunities in imaging, wavefront engineering, nonlinear optics, quantum information processing, just to name a few. The feature issue “Optical Metasurfaces: Fundamentals and Applications” in Photonics Research allows for archival publication of the most recent works in optical metasurface and provides for broad dissemination in the photonics community.

Structural color from artificial structures, due to its environmental friendliness and excellent durability, represents a route for color printing applications. Among various physical mechanisms, the Fabry–Perot (F–P) cavity effect provides a powerful way to generate vivid colors in either the reflection or transmission direction. Most of the previous F–P type color printing works rely on electron beam grayscale lithography, however, with this technique it is challenging to make large-area and low-cost devices. To circumvent this constraint, we propose to fabricate the F–P type color printing device by the laser grayscale lithography process. The F–P cavity consists of two thin silver films as mirrors and a photoresist film with a spatially variant thickness as the spacer layer. By controlling the laser exposure dose pixel by pixel, a centimeter-scale full-color printing device with a spatial resolution up to 5 μm × 5 μm is demonstrated. The proposed large area color printing device may have great potential in practical application areas such as color displays, hyperspectral imaging, advanced painting, and so on.

介电常数近零材料及相关物理现象近年来逐渐成为一个快速发展的研究领域。在介电常数近零材料中，光与物质相互作用显著增强，为设计新型光学功能器件提供了重要思路。从线性和非线性光学范畴综述了介电常数近零材料中光与物质相互作用的原理与应用进展。在线性光学部分，讨论了透明导电氧化物材料的光学性质、介电常数近零模式、载流子的电调控等方面的内容。在非线性光学部分，讨论了介电常数近零材料在非线性折射率调控、非线性频率转换以及时变ENZ材料中的非线性光学响应等方面的研究进展。最后，展望了介电常数近零材料领域的未来研究方向和应用领域。

Metasurface analogue of the phenomenon of electromagnetically induced transparency (EIT) that is originally observed in atomic gases offers diverse applications for new photonic components such as nonlinear optical units, slow-light devices, and biosensors. The development of functional integrated photonic devices requires an active control of EIT in metasurfaces. We demonstrate a reversible switching of the metasurface-induced transparency in the near-infrared region by incorporating a nonvolatile phase change material, Ge₂Sb₂Te₅, into the metasurface design. This leads to an ultrafast reconfigurable transparency window under an excitation of a nanosecond pulsed laser. The measurement agrees well with both theoretical calculation and finite-difference time-domain numerical simulation. Our work paves the way for dynamic metasurface devices such as reconfigurable slow light and biosensing.