damon yao

The development of flat, compact beam-steering devices with no bulky moving parts is opening up a new route to a variety of exciting applications, such as LIDAR scanning systems for autonomous vehicles, robotics and sensing, free-space, and even surface wave optical signal coupling. In this paper, the design, fabrication and characterization of innovative, nonvolatile, and reconfigurable beam-steering metadevices enabled by a combination of optical metasurfaces and chalcogenide phase-change materials is reported. The metadevices reflect an incident optical beam in a mirror-like fashion when the phase-change layer is in the crystalline state, but reflect anomalously at predesigned angles when the phase-change layer is switched into its amorphous state. Experimental angle-resolved spectrometry measurements verify that fabricated devices perform as designed, with high efficiencies, up to 40%, when operating at 1550 nm. Laser-induced crystallization and reamorphization experiments confirm reversible switching of the device. It is believed that reconfigurable phase-change-based beam-steering and beam-shaping metadevices, such as those reported here, can offer real applications advantages, such as high efficiency, compactness, fast switching times and, due to the nonvolatile nature of chalcogenide phase-change materials, low power consumption.

Beam-steering devices with no moving parts are likely to find widespread applications in areas such as LIDAR scanning systems for autonomous vehicles, robotics and sensing, telecommunications, and optical signal coupling. Here, the design, fabrication and characterization of innovative, fast, nonvolatile, and reconfigurable beam-steering devices enabled by a combination of optical metasurfaces and chalcogenide phase-change materials is reported.

Despite enormous efforts devoted to the development of high-performance batteries, the obtainable energy and power density, durability, and affordability of the existing batteries are still inadequate for many applications. Here, a self-standing nanostructured electrode with ultrafast cycling capability is reported by in situ tailoring Li₄Ti₅O₁₂ nanocrystals into a 3D carbon current collector (derived from filter paper) through a facile wet chemical process involving adsorption of titanium source, boiling treatment, and subsequent chemical lithiation. This 3D architectural electrode is charged/discharged to ≈60% of the theoretical capacity of Li₄Ti₅O₁₂ in ≈21 s at 100 C rate (17 500 mA g⁻¹ ), which also shows stable cycling performance for 1000 cycles at a cycling rate of 50 C. Additionally, modified 3D carbon current collector with much smaller pores and finer fiber diameters are further used, which significantly improve the specific capacity based on the weight of the entire electrode. These novel electrodes are promising for high-power applications such as electric vehicles and smart grids. This unique electrode architecture also simplifies the electrode fabrication process and significantly enhances current collection efficiency (especially at high rate). Further, the conceptual electrode design is applicable to other oxide electrode materials for high-performance batteries, fuel cells, and supercapacitors.

A novel electrode architecture is designed and realized by in situ tailoring of Li₄Ti₅O₁₂ nanocrystals into a 3D current collector (derived from filter paper) through a facile route. The electrode can be charged/discharged in 21 s (100 C) to ≈60% of its theoretical capacity and deliver an excellent cycling stability at 50 C.

3D AgX/graphene aerogel (GA) composites (X = Br, Cl) are synthesized. Not only is the photocatalytic performance increased in comparison with pristine AgX, but also the photocatalytic cycling process is facilitated just using tweezers Thus, the comprehensive performance of the AgX/GA composites provides robust support for future industrial applications of the photocatalyst.

On page 1656, S. Rosset, H. Shea, and colleagues present a soft, flexible, and deformable biomimetic lens based on dielectric elastomer actuators (a.k.a. artificial muscles) that is capable of electrically modulating its focal length by 20% in less than 200 microseconds.