Nanotechnology Spotlight – Latest Articles

Showing Spotlights 49 - 56 of 57 in category Metamaterials, Metasurfaces (newest first):

Computational and patterning approaches to realize metasurfaces in novel plasmonic materials

Compact optical components are crucial to realize miniaturized optical systems and integrated optoelectronic devices. Plasmonic metasurfaces - structured materials in 2D with rationally designed, subwavelength-scale building blocks - have drawn great interest because they can control light based on subwavelength structures. These planar devices are attractive for applications ranging from high resolution imaging to 3D holography. New work describes the design and prototyping of single-crystalline TiN plasmonic metasurfaces based on subwavelength hole arrays.

January 27, 2017

Full-color 3D meta-holography with a single nanostructured layer

Researchers have demonstrated that full-color 3D meta-holography imaging with extended viewing angles can be realized by a single layer of nanostructured metallic surface. In order to overcome the cross-talk among different colors that normally exists in current metasurface holography, the researchers introduced an off-axis illumination method to shift the holographic image in different colors and successfully reconstructed all visible colors in the imaging area. Taking advantages of the achromatic feature of the structure, the team also demonstrated full-color holography based on seven primary colors and 3D holographic imaging.

November 9, 2016

Ultra-thin achromatic lenses optimized by an evolutionary algorithm

Planar optical components are crucial to realize miniaturized optical systems and integrated optoelectronic devices. In particular, metasurfaces are of great interest for applications ranging from high resolution imaging to three-dimensional holography. Achromatic metasurfaces, which can maintain the same focal distance over a range of wavelengths, have been realized by engineering each subwavelength unit to induce an identical phase change at all wavelengths. However, the design method requires intensive computation. Researchers now have developed a highly efficient, universal algorithmic method based on evolutionary principles for the design of ultra-thin achromatic lenses.

October 28, 2016

A multifunctional biophotonic platform enabled by moire metasurfaces

Researchers demonstrate for the first time a multifunctional biophotonic platform enabled by the multiband resonance peaks of the plasmonic moire metasurfaces. Benefiting from the multiband nature of moire metasurface and the near-field enhancement from the metal-insulator-metal configuration, the scientists achieved a dual-band metasurface patch with strong plasmonic resonances at both near-infrared and mid-infrared regimes.The plasmonic nanostructures support plasmon resonances at different wavelengths due to the gradient in size and shape.

October 12, 2016

Moire Nanosphere Lithography allows fabrication of large-area tunable graphene metasurfaces

Graphene, one of the most exciting two-dimensional materials, has shown extraordinary optical properties due to strong surface plasmon polaritons supported by graphene nanostructure. Graphene metasurfaces show plasmonic resonance bands that can be tuned from mid-infrared to terahertz regime. These plasmonic devices can be used for biosensing, spectroscopy, light modulation and communication applications. Researchers now demonstrate for the first time an effective method to pattern large area graphene into moire metasurfaces with gradient nanostructures having multiband resonance peaks in mid infrared range.

August 16, 2016

Material scientists' fascination with negative Poisson's ratio

Poisson's ratio describes the fundamental elasticity of any solid. Poisson's ratio has been a basic principle of engineering for more than 200 years as it allows engineers to identify how much a material can be compressed and stretched and how much pressure it will withstand, before it collapses. Materials with a negative Poisson's ratio are relatively rare and it has recently become popular in referring to them as metamaterials - a group of materials that attain interesting or extreme properties via structure rather than composition.

August 3, 2016

Novel graphene-gold metasurface architecture provides significant gains in plasmonic detection sensitivity

With increasing sensitivity, electrical, mechanical and optical sensors are able to detect low molecular weight chemical and biological analytes under ever more dilute conditions. At the same time, though, researchers want to keep the sensing process as simple as possible without complex functionalization and complicated preparation steps for the in situ detection. A novel graphene-gold metasurface-based biosensing architectures makes extreme phase singularities possible due to a strong field enhancement on the graphene-gold interface.

September 14, 2015

Novel nanosphere lithography to fabricate tunable plasmonic metasurfaces

In conventional nanosphere lithography, the nanosphere configurations in the layers are determined by a spontaneous self-assembly process. Therefore, the final configurations are limited to those with or close to the minimal free energy giving rise to very simple patterns. Researchers have now managed to circumvent this thermodynamical restriction by putting the monolayers in a confined environment and constructing the bilayers with sequential stacking, both of which are critical for the formation of moire patterns.

June 18, 2015