Diffractive optical elements (DOEs) may be used as a single optical component with dedicated functionality (e.g. focusing), or as one of the elements in complex hybrid optical systems to reduce the number of the elements and improve imaging quality. It is desirable to cover DOE's surface with antireflective coating. In this paper, we show the results of simulations using the Fourier modal method and measure the efficiency of a diffractive lens with antireflective (AR) coating. Results were compared with a previously proposed model of AR covered DOE by Mao et al. [Opt. Express25, 11673 (2017)10.1364/OE.25.011673]. Contrary to the previously published model, we have not observed a shift of the efficiency curve. Our findings prove that AR coatings improve the efficiency of DOEs and it is not necessary to take them into account when calculating optimal profile height.
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http://dx.doi.org/10.1364/OE.422044 | DOI Listing |
Sci Rep
January 2025
School of Civil Engineering, Vellore Institute of Technology, Chennai, Tamil Nadu, 600127, India.
The carbon footprint associated with cement production, coupled with depletion of natural resources and climate change, underscores the need for sustainable alternatives. This study explores the effect of metakaolin (MK) and nano-silica (NS) on concrete's engineering performance and environmental impact. Initially, compressive, tensile, and flexural strength tests, along with durability assessments like water absorption, sorptivity, rapid chloride permeability, and resistance to acid and sulphate attacks, were conducted.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117580, Singapore.
Hydrate-based carbon capture and storage (HBCS) is a sustainable and promising approach to combating global warming by utilizing water, which is a ubiquitous resource. Here, we report a comprehensive study of CO hydrate formation in dry water (DW), a water-in-air dispersion confined in silica particles, for improving the kinetics of hydrate growth. Utilizing a combination of a home-built high-pressure reactor, in situ Raman spectroscopy, and powder X-ray diffraction (PXRD), we elucidate the crystal structure, growth dynamics, and morphology of CO hydrates formed in DW, with and without the kinetic hydrate promoter, l-tryptophan.
View Article and Find Full Text PDFActa Crystallogr F Struct Biol Commun
February 2025
Graduate School of Life Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
The bacterial enzyme tRNA 2-selenouridine synthase (SelU) catalyzes the conversion of 5-substituted 2-thiouridine (R5S2U) to 5-substituted 2-selenouridine (R5Se2U) at the wobble positions of several tRNAs. Seleno-modification potentially regulates translation efficiency in response to selenium availability. Notably, SelU uses the 2-geranylthiouridine (R5geS2U) intermediate for sulfur removal, and this geranylthiol (geS) is a unique leaving group among tRNA-maturation enzymes.
View Article and Find Full Text PDFLangmuir
January 2025
State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China.
Mineral precipitation is ubiquitous in natural and engineered environments, such as carbon mineralization, contaminant remediation, and oil recovery in unconventional reservoirs. The precipitation process continuously alters the medium permeability, thereby influencing fluid transport and subsequent reaction kinetics. The diversity of preferential precipitation zones controls flow and transport efficiency as well as the capacity of mineral sequestration and immobilization.
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January 2025
Key Laboratory for Information System of Mountainous Area and Protection of Ecological Environment of Guizhou Province, Guizhou Normal University, Guian, 550025, China.
Removal of accumulated dyes from the environment water bodies is essential to prevent further harm to humans. The development and design of new alternative nanoadsorbents that can conveniently, quickly, and efficiently improve the adsorption and removal efficiency of dyes from wastewater remains a huge challenge. An amorphous TiO with a magnetic core-shell-shell structure (FeO@PDA@a-TiO, denoted as FPaT) was constructed through a series of steps.
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