The reaction chemistry in the afterglow of a non-equilibrium, capacitive discharge, operated at 600 Torr total pressure with (0.5 to 5.0) × 10 17 cm -3 of oxygen in helium, has been examined by ultraviolet absorption spectroscopy, optical emission spectroscopy, and numerical modeling. The densities of the active species,and O 3 , have been determined as a function of the operating conditions. At RF power densities between 6.1 and 30.5 W/cm 3 and a neutral temperature of 100 ( 40°C, the plasma generated (0.2 to 1.0) × 10 16 cm -3 of O( 3 P) and O 2 ( 1 ∆ g ), (0.2 to 2.0) × 10 15 cm -3 of O 2 ( 1 Σ g + ), and (0.1 to 4.0) × 10 15 cm -3 of O 3 . After the power was turned off, the singlet-sigma and singlet-delta states decayed within 0.1 and 30.0 ms, respectively. The concentration of oxygen atoms remained constant for about 0.5 ms, then fell rapidly due to recombination with O 2 to form O 3 . It was found that the etching rate of polyimide correlated with the concentration of oxygen atoms in the afterglow, indicating that the O atoms were the active species involved in this process.

Janus monolayers, a class of two‐faced 2D materials, have received significant attention in electronics, due to their unusual conduction properties stemming from their inherent out‐of‐plane asymmetry. Their photonic counterparts recently allowed for the control of hydrogenation/dehydrogenation processes, yielding drastically different responses for opposite light excitation spins. A passive Janus metasurface composed of cascaded subwavelength anisotropic impedance sheets is demonstrated. By introducing a rotational twist in their geometry, asymmetric transmission with the desired phase function is realized. Their broken out‐of‐plane symmetry realizes different functions for opposite propagation directions, enabling direction‐dependent versatile functionalities. A series of passive Janus metasurfaces that enable functionalities including one‐way anomalous refraction, one‐way focusing, asymmetric focusing, and direction‐controlled holograms are experimentally demonstrated.

Artificially engineered metasurfaces provide extraordinary wave control at the subwavelength scale. However, metasurfaces proposed so far suffer due to limited bandwidths. In this paper, extremely thin metasurfaces made of single metallic layer is experimentally presented for ultra‐wideband operation from 9.3 to 32.5 GHz (with a fractional band of 112%), working at both transmission and reflection modes simultaneously. The phase control is achieved by azimuthally rotating the scatterer based on Pancharatnam–Berry phase principle. Nearly uniform efficiency (≈25%), approaching the theoretical limit of the infinitely thin metasurface, is achieved throughout the operation band. Finally, the proposed design is implemented for applications, e.g., the generation of electromagnetic waves carrying orbital angular momentums as well as anomalous reflections and refractions. The metasurfaces are characterized numerically and experimentally and the results are in good agreements.

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Letter to the EditorMolecular Plant molecular mechanisms involved in the Cd hyperaccumulation and hypertolerance of S. plumbizincicola. ACCESSION NUMBERSThe RNA-seq data of this study have been deposited in Gene Expression Omnibus (GEO) under the accession number GEO: GSE92529.

The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C), with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

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