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Metamaterials - OSTI GOV

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Last Updated: 23 April 2022

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Imaging collective behavior in an rf-SQUID metamaterial tuned by DC and RF magnetic fields

We image microwave currents in the driven SQUIDs in non-radiating dark modes by using low-temperature laser scanning microscopy to determine the clustering and uniformity of like-oscillating meta-atoms. We track coherent patterns due to meta-atom resonant frequency tuning, as a result of external dc and rf magnetic flux biases. We find that the rf current distribution across the SQUID array at zero dc flux and small rf flux shows a poor degree of coherence.

Source link: https://www.osti.gov/biblio/1604585


Tunable optical metamaterial-based sensors enabled by closed bipolar electrochemistry

We develop and characterization a chemical sensing technique based on electrochemical calibration of large-area, inexpensive nanoaperture metamaterials' optical response function at visible and near-IR wavelengths. In a Au film, a Nanosphere lithography is used to produce an ordered array of sub-wavelength apertures. Optical transmission spectra obtained under galvanostatic conditions can be characterized as a linear combination of the initial and final spectra, with the resulting response function showing a sigmoidal response with respect to the amount of charge deposit. The analyte cell's exposed electrode area increases the response of the device, while changing the circuit resistance changes the balance between sensitivity and dynamic range. These tunable nanoaperture metamaterials have increased sensitivity to the nM to nM concentration range when compared to CBE electrochromic reporter cells, opening up new avenues for the manufacture of CBE-based chemical sensors as well as the application of inexpensive, point-of-care diagnostic kits.

Source link: https://www.osti.gov/biblio/1800400


Creating metamaterial building blocks with directed photochemical metallization of silver onto DNA origami templates

DNA origami can be used to design a variety of intricate and geometrically unique nanostructures that can be further expanded to produce building blocks for applications such as optical metamaterials. The DNA origami template is used as a localized photosensitizer to aid in the reduction of silver ions directly from solution to the DNA surface. This coating process, however, shows the shape of the original DNA template's continuous and uniform metal layer, which leads to a metal nanostructure that maps the original DNA template's shape with a continuous and uniform metal layer and stops expanding until all available DNA sites are exhausted.

Source link: https://www.osti.gov/biblio/1460379


Formation of rarefaction waves in origami-based metamaterials

paraphrasedoutput cells of Tachi-Miura polyhedron unit cells. Here, we investigate the nonlinear wave dynamics of origami-based metamaterials composed of Tachi-Miura polyhedron unit cells. We assemble these TMP cells into a stack of origami-based metamaterials and mathematically measure their wave transmission behavior under external influence. According to Numerical experiments, origami-based metamaterials can provide a prototypical platform for the synthesis of nonlinear coherent structures in the form of rarefaction waves, which feature a tensile wavefront on application of compression to the device.

Source link: https://www.osti.gov/biblio/1257858


All-dielectric metasurface analogue of electromagnetically induced transparency [High Quality Factor Fano-Resonant All-Dielectric Metamaterials]

Because of their ability to produce high quality factor resonances, the nanophotonics fields have been a significant focus of the nanophotonics fields over the past several years. In addition, the unit cell of the metamaterial was constructed with a feed-gap, which results in significant local field expansion in the surrounding medium, which resultes in good light-matter interaction. This allows the metamaterial to be used as a refractive index sensor with a figure-of-merit of 101, much higher than the previous reported localized surface plasmon resonance sensors' performance.

Source link: https://www.osti.gov/biblio/1185509


Tailoring photonic metamaterial resonances for thermal radiation

Selective solar absorbers have limited effectiveness in unconcentrated sunlight due to reradiation losses in a wide variety of wavelengths and angles. We find thermal transfer efficiencies of 78% at temperatures over 1,000°C, exceeding the Shockley-Quiesser efficiencies ceiling of 31% for photovoltaic conversion under unconcentrated sunlight.

Source link: https://www.osti.gov/biblio/1386878

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions