Invisible surfaces enabled by the coalescence of anti-reflection and wavefront controllability in ultrathin metasurfaces

Reflection inherently occurs on the interfaces between different media. In order to perfectly manipulate waves on the interfaces, integration of antireflection function in metasurfaces is highly desired. In this work, we demonstrate an approach to realize exceptional metasurfaces that combine the two vital functionalities of antireflection and arbitrary phase manipulation in the deep subwavelength scale. Such ultrathin devices confer reflection-less transmission through impedance-mismatched interfaces with arbitrary wavefront shapes. Theoretically and experimentally, we demonstrate a three-layer antireflection metasurface that achieves an intriguing phenomenon: the simultaneous elimination of the reflection and refraction effects on a dielectric surface. Incident waves transmit straightly through the dielectric surface as if the surface turns invisible. We further demonstrate a wide variety of applications such as invisible curved surfaces, “cloaking” of dielectric objects, reflection-less negative refraction and flat axicons on dielectric-air interfaces, etc. The coalescence of antireflection and wavefront controllability in the deep subwavelength scale brings new opportunities for advanced interface optics with high efficiency and great flexibility.

In situ decoration of La(OH)3 on polyethyleneimine linked dendritic mesoporous silica nanospheres targeting at efficient and simultaneous removal of phosphate and Congo red

The simultaneous elimination of phosphorus and dye is of great significance for the practical treatment of dye-containing wastewater. In this study, a series of novel mesoporous adsorbents were successfully fabricated...

Reserves of teaching staff's productivity growth based on lean technologies

The purpose of this study is to find and justify reserves for increasing the productivity of teachers on the example of the Novosibirsk State Technical University. Some of the methods presented in the paper are well-known and are of interest from a practical point of view. These include a survey, observation, experiment, and in-depth interview. Some methods are specific and are more often used by experts in the field of lean manufacturing. The key set of lean tools was the kaizen umbrella, which includes the philosophy of continuous improvement, the method of mapping the value stream, the “five why” method. Diagrams of various purposes are widely used in the article: Ishikawa, Pareto, spaghetti. The main problem solved in this paper is a large number of errors in syllabuses, a long time of their creation and excessive control. The hypothesis about the simultaneous elimination of these shortcomings by automating the process itself was tested. The experiment proved the validity of the hypothesis. The duration of the value creation process during the development of syllabuses was reduced by 15%, and the overall satisfaction of the participants in the process increased by 27.5%. The total savings of the working time fund amounted to 0.5 million man-hours across the entire university, accounting for almost 100 thousand syllabuses.