Wednesday, October 2, 2019

Engineering Phonon Polaritons In Van Der Waals Heterostructures To Enhance In Plane Optical Anisotropy

Van der Waals (vdW) heterostructures assembled from layers of two-dimensional materials have attracted considerable interest due to their novel optical and electrical properties! Engineering phonon polaritons in van der Waals ...ad van ...Engineering phonon polaritons in van der Waals heterostructures to enhance in-plane optical anisotropy By Kundan Chaudhary , Michele Tamagnone , Mehdi Rezaee , D. Kwabena Bediako , Antonio Ambrosio , Philip Kim , Federico Capasso!! Here, we report a scattering-type scanning near-field optical microscopy study of hexagonal boron nitride on black phosphorus (h-BN/BP) heterostructures, demonstrating the first direct observation of in-plane anisotropic phonon polariton modes in vdW heterostructures! (PDF) Engineering phonon polaritons in van der Waals ...Engineering _ phonon _ polaritons _in...Engineering phonon polaritons in van der Waals heterostructures to enhance in-plane optical anisotropy Article (PDF Available) in Science Advances 5(4):eaau7171 · April 2019 with 69 Reads!! Notably, the measured in-plane optical anisotropy along the armchair and zigzag crystal axes exceeds the ratio of refractive indices of BP in the x-y plane. We explain that this enhancement is due to the high confinement of the phonon polaritons in h-BN. We observe a maximum in-plane optical anisotropy of αmax = 1.25 in the frequency spectrum at 1405 to 1440 cm−1. These results provide new insights into the behavior of polaritons in vdW heterostructures, and the observed anisotropy enhancement paves the way to novel nanophotonic devices and to a new way to characterize optical anisotropy in thin films.

Publisher: Science Advances
Date: 2019-04-01
Reference: Visit Source



This may worth something:

Binodal, wireless epidermal electronic systems with in-sensor analytics for neonatal intensive care
Neonatal care, particularly for premature babies, is complicated by the infants' fragility and by the need for a large number of tethered sensors to be attached to their tiny bodies! Engineering Phonon Polaritons in van der Waals ...Engineering _ Phonon _ Polaritons _in...They range from light waves or surface plasmons in nanoplasmonic devices to sound waves in acoustic-metamaterial waveguides, as well as fermions and phonon polaritons in graphene and van der Waals ...!! Chung et al. developed a pair of sensors that only require water to adhere to the skin and allow for untethered monitoring of key vital signs (see the Perspective by Guinsburg). On-board data processing allowed for efficient wireless near-field communication using standard protocols! Title: Engineering Phonon Polaritons in van der Waals ...Engineering Phonon Polaritons in van der Waals Heterostructures to Enhance In-Plane Optical Anisotropy Authors: Kundan Chaudhary1‡, Michele Tamagnone1‡, Mehdi Rezaee 1,2‡, D. Kwabena Bediako 3, Antonio Ambrosio 4, Philip Kim 3, Federico Capasso 1* Affiliations: 1Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University,!! The absence of cables makes it easier to handle the infants and allows for skin-to-skin contact between the babies and their parents or caregivers


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In neonatal intensive care units (NICUs), continuous monitoring of vital signs is essential, particularly in cases of severe prematurity! [1807.03339] Engineering Phonon Polaritons in van der ...arxiv.org/abs/1807.03339 Abstract: Van der Waals heterostructures assembled from layers of 2D materials have attracted considerable interest due to their novel optical and electrical properties. Here we report a scattering-type scanning near field optical microscopy study of hexagonal boron nitride on black phosphorous (h-BN/BP) heterostructures, demonstrating the first direct observation of in-plane anisotropic ...!! Current monitoring platforms require multiple hard-wired, rigid interfaces to a neonate's fragile, underdeveloped skin and, in some cases, invasive lines inserted into their delicate arteries. These platforms and their wired interfaces pose risks for iatrogenic skin injury, create physical barriers for skin-to-skin parental/neonate bonding, and frustrate even basic clinical tasks. Technologies that bypass these limitations and provide additional, advanced physiological monitoring capabilities would directly address an unmet clinical need for a highly vulnerable population.

Publisher: Science
Date: 2019-03-01
Author: Ha Uk Chung
Reference: Visit Source



Trump, DeVos bungle Special Olympics budget | TheHill
In two separate congressional hearings, DeVos found herself defending the cuts in Trump's 2020 spending request, only to have the president turn around and denounce his own proposal


The contrasting positions played out amid a backdrop of lawmakers grilling agency chiefs about draconian cuts to popular government programs, leaving administration officials with the choice of defending the spending reductions or disagreeing with Trump, who is known to prize loyalty among his Cabinet members


DeVos went before appropriators to defend the administration's proposal to slash $8.5 billion, or 12 percent, from the education budget


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But appropriators seized on the $18 million cut for the Special Olympics, the world's largest sporting event for adults with disabilities. Trump has proposed cutting funding to it in each of his three annual budget proposals.

Publisher: TheHill
Date: 2019-03-29T17:56:39-04:00
Author: Niv Elis
Reference: Visit Source



A large impact crater beneath Hiawatha Glacier in northwest Greenland | Science Advances

We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact-related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron asteroid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.

Publisher: Science Advances
Date: 2018-11-01
Reference: Visit Source



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