1,432 research outputs found
Problematising upstream technology through speculative design: the case of quantified cats and dogs
There is growing interest in technology that quantifies aspects of our lives. This paper draws on critical practice and speculative design to explore, question and problematise the ultimate consequences of such technology using the quantification of companion animals (pets) as a case study. We apply the concept of âmoving upstreamâ to study such technology and use a qualitative research approach in which both pet owners, and animal behavioural experts, were presented with, and asked to discuss, speculative designs for pet quantification applications, the design of which were extrapolated from contemporary trends. Our findings indicate a strong desire among pet owners for technology that has little scientific justification, whilst our experts caution that the use of technology to augment human-animal communication has the potential to disimprove animal welfare, undermine human-animal bonds, and create human-human conflicts. Our discussion informs wider debates regarding quantification technology
Circular dichroism induced by Fano resonances in planar chiral oligomers
We present a general theory of circular dichroism in planar chiral
nanostructures with rotational symmetry. It is demonstrated, analytically, that
the handedness of the incident field's polarization can control whether a
nanostructure induces either absorption or scattering losses, even when the
total optical loss (extinction) is polarization-independent. We show that this
effect is a consequence of modal interference so that strong circular dichroism
in absorption and scattering can be engineered by combining Fano resonances
with planar chiral nanoparticle clusters.Comment: 12 pages, 5 figure
Interplay of magnetic responses in all-dielectric oligomers to realize magnetic Fano resonances
We study the interplay between collective and individual optically-induced
magnetic responses in quadrumers made of identical dielectric nanoparticles.
Unlike their plasmonic counterparts, all-dielectric nanoparticle clusters are
shown to exhibit multiple dimensions of resonant magnetic responses that can be
employed for the realization of anomalous scattering signatures. We focus our
analysis on symmetric quadrumers made from silicon nanoparticles and verify our
theoretical results in proof-of-concept radio frequency experiments
demonstrating the existence of a novel type of magnetic Fano resonance in
nanophotonics.Comment: 20 pages, 7 figure
Optical chirality from dark-field illumination of planar plasmonic nanostructures
Dark-field illumination is shown to make planar chiral nanoparticle
arrangements exhibit circular dichroism in extinction analogous to true chiral
scatterers. Circular dichrosim is experimentally observed at the maximum
scattering of single oligomers consisting rotationally symmetric arrangements
of gold nanorods, with strong agreement to numerical simulation. A dipole model
is developed to show that this effect is caused by a difference in the
geometric projection of a nanorod onto the handed orientation of electric
fields created by a circularly polarized dark-field that is normally incident
on a glass substrate. Owing to this geometric origin, the wavelength of the
peak chiral response is also experimentally shown to shift depending on the
separation between nanoparticles. All presented oligomers have physical
dimensions less than the operating wavelength, and the applicable extension to
closely packed planar arrays of oligomers is demonstrated to amplify the
magnitude of circular dichroism. The realization of strong chirality in these
oligomers demonstrates a new path to engineer optical chirality from planar
devices using dark-field illumination
Revisiting the physics of Fano resonances for nanoparticle oligomers
We present a robust approach for interpreting the physics of Fano resonances in planar oligomer structures of both metallic and dielectric nanoparticles. We reveal a key mechanism for Fano resonances by demonstrating that such resonances can be generate
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